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Merge pull request #8 from pwpiwi/master

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add .gitignore and merge svn r852
This commit is contained in:
holiman 2014-03-25 21:49:05 +01:00
commit f5a1a9ce47
8 changed files with 505 additions and 369 deletions
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27
.gitignore vendored Normal file
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@ -0,0 +1,27 @@
# .gitignore
# don't push these files to the repository
*.o
*.a
*.d
*.elf
*.s19
*.map
*.bin
*.dll
*.moc.cpp
*.exe
proxmark
flasher
version.c
fpga/*
!fpga/fpga.bit
!fpga/*.v
!fpga/Makefile
!fpga/fpga.ucf
!fpga/xst.scr
!fpga/go.bat
!fpga/sim.tcl

4
armsrc/fpgaloader.c
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@ -115,11 +115,11 @@ void FpgaSetupSsc(void)
AT91C_BASE_SSC->SSC_RCMR = SSC_CLOCK_MODE_SELECT(1) | SSC_CLOCK_MODE_START(1);
// 8 bits per transfer, no loopback, MSB first, 1 transfer per sync
// pulse, no output sync, start on positive-going edge of sync
// pulse, no output sync
AT91C_BASE_SSC->SSC_RFMR = SSC_FRAME_MODE_BITS_IN_WORD(8) | AT91C_SSC_MSBF | SSC_FRAME_MODE_WORDS_PER_TRANSFER(0);
// clock comes from TK pin, no clock output, outputs change on falling
// edge of TK, sample on rising edge of TK
// edge of TK, sample on rising edge of TK, start on positive-going edge of sync
AT91C_BASE_SSC->SSC_TCMR = SSC_CLOCK_MODE_SELECT(2) | SSC_CLOCK_MODE_START(5);
// tx framing is the same as the rx framing

71
armsrc/iso14443a.c
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@ -42,15 +42,14 @@ static uint8_t iso14_pcb_blocknum = 0;
//
// Total delays including SSC-Transfers between ARM and FPGA. These are in carrier clock cycles (1/13,56MHz)
//
// When the PM acts as reader and is receiving, it takes
// 3 ticks for the A/D conversion
// 10 ticks ( 16 on average) delay in the modulation detector.
// 6 ticks until the SSC samples the first data
// 7*16 ticks to complete the transfer from FPGA to ARM
// 8 ticks to the next ssp_clk rising edge
// When the PM acts as reader and is receiving tag data, it takes
// 3 ticks delay in the AD converter
// 16 ticks until the modulation detector completes and sets curbit
// 8 ticks until bit_to_arm is assigned from curbit
// 8*16 ticks for the transfer from FPGA to ARM
// 4*16 ticks until we measure the time
// - 8*16 ticks because we measure the time of the previous transfer
#define DELAY_AIR2ARM_AS_READER (3 + 10 + 6 + 7*16 + 8 + 4*16 - 8*16)
#define DELAY_AIR2ARM_AS_READER (3 + 16 + 8 + 8*16 + 4*16 - 8*16)
// When the PM acts as a reader and is sending, it takes
// 4*16 ticks until we can write data to the sending hold register
@ -61,15 +60,15 @@ static uint8_t iso14_pcb_blocknum = 0;
#define DELAY_ARM2AIR_AS_READER (4*16 + 8*16 + 8 + 8 + 1)
// When the PM acts as tag and is receiving it takes
// 12 ticks delay in the RF part,
// 2 ticks delay in the RF part (for the first falling edge),
// 3 ticks for the A/D conversion,
// 8 ticks on average until the start of the SSC transfer,
// 8 ticks until the SSC samples the first data
// 7*16 ticks to complete the transfer from FPGA to ARM
// 8 ticks until the next ssp_clk rising edge
// 3*16 ticks until we measure the time
// 4*16 ticks until we measure the time
// - 8*16 ticks because we measure the time of the previous transfer
#define DELAY_AIR2ARM_AS_TAG (12 + 3 + 8 + 8 + 7*16 + 8 + 3*16 - 8*16)
#define DELAY_AIR2ARM_AS_TAG (2 + 3 + 8 + 8 + 7*16 + 8 + 4*16 - 8*16)
// The FPGA will report its internal sending delay in
uint16_t FpgaSendQueueDelay;
@ -78,29 +77,30 @@ uint16_t FpgaSendQueueDelay;
#define DELAY_FPGA_QUEUE (FpgaSendQueueDelay<<1)
// When the PM acts as tag and is sending, it takes
// 5*16 ticks until we can write data to the sending hold register
// 4*16 ticks until we can write data to the sending hold register
// 8*16 ticks until the SHR is transferred to the Sending Shift Register
// 8 ticks until the first transfer starts
// 8 ticks later the FPGA samples the data
// + a varying number of ticks in the FPGA Delay Queue (mod_sig_buf)
// + 1 tick to assign mod_sig_coil
#define DELAY_ARM2AIR_AS_TAG (5*16 + 8*16 + 8 + 8 + DELAY_FPGA_QUEUE + 1)
#define DELAY_ARM2AIR_AS_TAG (4*16 + 8*16 + 8 + 8 + DELAY_FPGA_QUEUE + 1)
// When the PM acts as sniffer and is receiving tag data, it takes
// 3 ticks A/D conversion
// 16 ticks delay in the modulation detector (on average).
// + 16 ticks until it's result is sampled.
// 14 ticks to complete the modulation detection
// 8 ticks (on average) until the result is stored in to_arm
// + the delays in transferring data - which is the same for
// sniffing reader and tag data and therefore not relevant
#define DELAY_TAG_AIR2ARM_AS_SNIFFER (3 + 16 + 16)
#define DELAY_TAG_AIR2ARM_AS_SNIFFER (3 + 14 + 8)
// When the PM acts as sniffer and is receiving tag data, it takes
// 12 ticks delay in analogue RF receiver
// When the PM acts as sniffer and is receiving reader data, it takes
// 2 ticks delay in analogue RF receiver (for the falling edge of the
// start bit, which marks the start of the communication)
// 3 ticks A/D conversion
// 8 ticks on average until we sample the data.
// 8 ticks on average until the data is stored in to_arm.
// + the delays in transferring data - which is the same for
// sniffing reader and tag data and therefore not relevant
#define DELAY_READER_AIR2ARM_AS_SNIFFER (12 + 3 + 8)
#define DELAY_READER_AIR2ARM_AS_SNIFFER (2 + 3 + 8)
//variables used for timing purposes:
//these are in ssp_clk cycles:
@ -258,23 +258,7 @@ void UartReset()
Uart.endTime = 0;
}
/* inline RAMFUNC Modulation_t MillerModulation(uint8_t b)
{
// switch (b & 0x88) {
// case 0x00: return MILLER_MOD_BOTH_HALVES;
// case 0x08: return MILLER_MOD_FIRST_HALF;
// case 0x80: return MILLER_MOD_SECOND_HALF;
// case 0x88: return MILLER_MOD_NOMOD;
// }
// test the second cycle for a pause. For whatever reason the startbit tends to appear earlier than the rest.
switch (b & 0x44) {
case 0x00: return MOD_BOTH_HALVES;
case 0x04: return MOD_FIRST_HALF;
case 0x40: return MOD_SECOND_HALF;
default: return MOD_NOMOD;
}
}
*/
// use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
{
@ -398,10 +382,10 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
static tDemod Demod;
// Lookup-Table to decide if 4 raw bits are a modulation.
// We accept three or four consecutive "1" in any position
// We accept three or four "1" in any position
const bool Mod_Manchester_LUT[] = {
FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE,
FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE, TRUE
FALSE, FALSE, FALSE, TRUE, FALSE, TRUE, TRUE, TRUE
};
#define IsManchesterModulationNibble1(b) (Mod_Manchester_LUT[(b & 0x00F0) >> 4])
@ -646,7 +630,7 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
previous_data = *data;
rsamples++;
data++;
if(data > dmaBuf + DMA_BUFFER_SIZE) {
if(data == dmaBuf + DMA_BUFFER_SIZE) {
data = dmaBuf;
}
} // main cycle
@ -1423,7 +1407,7 @@ static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, bool correctionNeeded)
i = 1;
}
// clear receiving shift register and holding register
// clear receiving shift register and holding register
while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
b = AT91C_BASE_SSC->SSC_RHR; (void) b;
while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
@ -2593,11 +2577,12 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
//May just aswell send the collected ar_nr in the response aswell
cmd_send(CMD_ACK,CMD_SIMULATE_MIFARE_CARD,0,0,&ar_nr_responses,ar_nr_collected*4*4);
}
if(flags & FLAG_NR_AR_ATTACK)
{
if(ar_nr_collected > 1) {
Dbprintf("Collected two pairs of AR/NR which can be used to extract keys from reader:");
Dbprintf("../tools/mfkey/mfkey32 %08x %08x %08x %08x",
Dbprintf("../tools/mfkey/mfkey32 %08x %08x %08x %08x %08x %08x",
ar_nr_responses[0], // UID
ar_nr_responses[1], //NT
ar_nr_responses[2], //AR1
@ -2608,7 +2593,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
} else {
Dbprintf("Failed to obtain two AR/NR pairs!");
if(ar_nr_collected >0) {
Dbprintf("Only got these: UID=%08d, nonce=%08d, AR1=%08d, NR1=%08d",
Dbprintf("Only got these: UID=%08x, nonce=%08x, AR1=%08x, NR1=%08x",
ar_nr_responses[0], // UID
ar_nr_responses[1], //NT
ar_nr_responses[2], //AR1
@ -2762,7 +2747,7 @@ void RAMFUNC SniffMifare(uint8_t param) {
previous_data = *data;
sniffCounter++;
data++;
if(data > dmaBuf + DMA_BUFFER_SIZE) {
if(data == dmaBuf + DMA_BUFFER_SIZE) {
data = dmaBuf;
}

3
armsrc/mifaresniff.c
View file

@ -93,7 +93,8 @@ bool RAMFUNC MfSniffLogic(const uint8_t *data, uint16_t len, uint32_t parity, ui
}
case SNF_ANTICOL2:{
if ((!reader) && (len == 5) && ((data[0] ^ data[1] ^ data[2] ^ data[3]) == data[4])) { // CL2 UID
memcpy(sniffUID, data, 4);
memcpy(sniffUID, sniffUID+4, 3);
memcpy(sniffUID+3, data, 4);
sniffUIDType = SNF_UID_7;
sniffState = SNF_UID2;
}

2
armsrc/util.c
View file

@ -363,8 +363,6 @@ void StartCountSspClk()
//
while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME)); // wait for ssp_frame to go high (start of frame)
while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME); // wait for ssp_frame to be low
// after the falling edge of ssp_frame, there is delay of 1/13,56MHz (73ns) until the next rising edge of ssp_clk. This are only a few
// processor cycles. We therefore may or may not be able to sync on this edge. Therefore better make sure that we miss it:
while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high
// note: up to now two ssp_clk rising edges have passed since the rising edge of ssp_frame
// it is now safe to assert a sync signal. This sets all timers to 0 on next active clock edge

10
client/cmdhfmf.c
View file

@ -1883,8 +1883,9 @@ int CmdHF14AMfSniff(const char *Cmd){
printf("Press the key on pc keyboard to abort the client.\n");
printf("-------------------------------------------------------------------------\n");
UsbCommand c = {CMD_MIFARE_SNIFFER, {0, 0, 0}};
SendCommand(&c);
UsbCommand c = {CMD_MIFARE_SNIFFER, {0, 0, 0}};
clearCommandBuffer();
SendCommand(&c);
// wait cycle
while (true) {
@ -1931,7 +1932,7 @@ int CmdHF14AMfSniff(const char *Cmd){
sak = bufPtr[11];
PrintAndLog("tag select uid:%s atqa:%02x %02x sak:0x%02x", sprint_hex(uid, 7), atqa[0], atqa[1], sak);
if (wantLogToFile) {
if (wantLogToFile || wantDecrypt) {
FillFileNameByUID(logHexFileName, uid, ".log", 7);
AddLogCurrentDT(logHexFileName);
}
@ -1947,7 +1948,8 @@ int CmdHF14AMfSniff(const char *Cmd){
}
} // resp not NILL
} // while (true)
return 0;
return 0;
}
static command_t CommandTable[] =

BIN
fpga/fpga.bit
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Binary file not shown.

755
fpga/hi_iso14443a.v
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@ -29,28 +29,64 @@ module hi_iso14443a(
output dbg;
input [2:0] mod_type;
reg ssp_clk;
reg ssp_frame;
wire adc_clk;
assign adc_clk = ck_1356meg;
wire adc_clk = ck_1356meg;
reg after_hysteresis, pre_after_hysteresis, after_hysteresis_prev1, after_hysteresis_prev2, after_hysteresis_prev3, after_hysteresis_prev4;
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Reader -> PM3:
// detecting and shaping the reader's signal. Reader will modulate the carrier by 100% (signal is either on or off). Use a
// hysteresis (Schmitt Trigger) to avoid false triggers during slowly increasing or decreasing carrier amplitudes
reg after_hysteresis;
reg [11:0] has_been_low_for;
reg [8:0] saw_deep_modulation;
reg [2:0] deep_counter;
reg deep_modulation;
always @(negedge adc_clk)
begin
if(& adc_d[7:6]) after_hysteresis <= 1'b1; // adc_d >= 196 (U >= 3,28V) -> after_hysteris = 1
else if(~(| adc_d[7:4])) after_hysteresis <= 1'b0; // if adc_d <= 15 (U <= 1,13V) -> after_hysteresis = 0
if(adc_d >= 16) after_hysteresis <= 1'b1; // U >= 1,14V -> after_hysteresis = 1
else if(adc_d < 8) after_hysteresis <= 1'b0; // U < 1,04V -> after_hysteresis = 0
// Note: was >= 3,53V and <= 1,19V. The new trigger values allow more reliable detection of the first bit
// (it might not reach 3,53V due to the high time constant of the high pass filter in the analogue RF part).
// In addition, the new values are more in line with ISO14443-2: "The PICC shall detect the ”End of Pause” after the field exceeds
// 5% of H_INITIAL and before it exceeds 60% of H_INITIAL." Depending on the signal strength, 60% might well be less than 3,53V.
pre_after_hysteresis <= after_hysteresis;
// detecting a loss of reader's field (adc_d < 192 for 4096 clock cycles). If this is the case,
// set the detected reader signal (after_hysteresis) to '1' (unmodulated)
if(adc_d >= 192)
begin
has_been_low_for <= 12'd0;
end
else
begin
if(has_been_low_for == 12'd4095)
begin
has_been_low_for <= 12'd0;
after_hysteresis <= 1'b1;
end
else
begin
has_been_low_for <= has_been_low_for + 1;
end
end
end
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Reader -> PM3
// detect when a reader is active (modulating). We assume that the reader is active, if we see the carrier off for at least 8
// carrier cycles. We assume that the reader is inactive, if the carrier stayed high for at least 256 carrier cycles.
reg deep_modulation;
reg [2:0] deep_counter;
reg [8:0] saw_deep_modulation;
always @(negedge adc_clk)
begin
if(~(| adc_d[7:0])) // if adc_d == 0 (U <= 0,94V)
begin
if(deep_counter == 3'd7) // adc_d == 0 for 7 adc_clk ticks -> deep_modulation (by reader)
if(deep_counter == 3'd7) // adc_d == 0 for 8 adc_clk ticks -> deep_modulation (by reader)
begin
deep_modulation <= 1'b1;
saw_deep_modulation <= 8'd0;
@ -61,136 +97,147 @@ begin
else
begin
deep_counter <= 3'd0;
if(saw_deep_modulation == 8'd255) // adc_d != 0 for 255 adc_clk ticks -> deep_modulation is over, now waiting for tag's response
if(saw_deep_modulation == 8'd255) // adc_d != 0 for 256 adc_clk ticks -> deep_modulation is over, probably waiting for tag's response
deep_modulation <= 1'b0;
else
saw_deep_modulation <= saw_deep_modulation + 1;
end
if(after_hysteresis)
begin
has_been_low_for <= 12'd0;
end
else
begin
if(has_been_low_for == 12'd4095)
begin
has_been_low_for <= 12'd0;
after_hysteresis <= 1'b1; // reset after_hysteresis to 1 if it had been 0 for 4096 cycles (no field)
end
else
begin
has_been_low_for <= has_been_low_for + 1;
end
end
end
// Report every 4 subcarrier cycles
// 128 periods of carrier frequency => 7-bit counter [negedge_cnt]
reg [6:0] negedge_cnt;
reg bit1, bit2, bit3, bit4;
reg curbit;
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Tag -> PM3
// filter the input for a tag's signal. The filter box needs the 4 previous input values and is a gaussian derivative filter
// for noise reduction and edge detection.
// store 4 previous samples:
reg [7:0] input_prev_4, input_prev_3, input_prev_2, input_prev_1;
// convert to signed signals (and multiply by two for samples at t-4 and t)
wire signed [10:0] input_prev_4_times_2 = {0, 0, input_prev_4, 0};
wire signed [10:0] input_prev_3_times_1 = {0, 0, 0, input_prev_3};
wire signed [10:0] input_prev_1_times_1 = {0, 0, 0, input_prev_1};
wire signed [10:0] adc_d_times_2 = {0, 0, adc_d, 0};
// storage for four previous samples:
reg [7:0] adc_d_1;
reg [7:0] adc_d_2;
reg [7:0] adc_d_3;
reg [7:0] adc_d_4;
// the filtered signal (filter performs noise reduction and edge detection)
// (gaussian derivative)
wire signed [10:0] tmp_1, tmp_2;
wire signed [10:0] adc_d_filtered;
assign adc_d_filtered = (adc_d_4 << 1) + adc_d_3 - adc_d_1 - (adc_d << 1);
integer i;
// Registers to store steepest edges detected:
reg [7:0] rx_mod_falling_edge_max;
reg [7:0] rx_mod_rising_edge_max;
assign tmp_1 = input_prev_4_times_2 + input_prev_3_times_1;
assign tmp_2 = input_prev_1_times_1 + adc_d_times_2;
// A register to send 8 Bit results to the arm
reg [7:0] to_arm;
reg bit_to_arm;
reg fdt_indicator, fdt_elapsed;
reg [10:0] fdt_counter;
//reg [47:0] mod_sig_buf;
reg [31:0] mod_sig_buf;
//reg [5:0] mod_sig_ptr;
reg [4:0] mod_sig_ptr;
reg [3:0] mod_sig_flip;
reg mod_sig, mod_sig_coil;
reg temp_buffer_reset;
reg sendbit;
reg [3:0] sub_carrier_cnt;
reg[3:0] reader_falling_edge_time;
// ADC data appears on the rising edge, so sample it on the falling edge
always @(negedge adc_clk)
begin
// ------------------------------------------------------------------------------------------------------------------------------------------------------------------
// relevant for TAGSIM_MOD only. Timing of Tag's answer relative to a command received from a reader
// ISO14443-3 specifies:
// fdt = 1172, if last bit was 0.
// fdt = 1236, if last bit was 1.
// the FPGA takes care for the 1172 delay. To achieve the additional 1236-1172=64 ticks delay, the ARM must send an additional correction bit (before the start bit).
// The correction bit will be coded as 00010000, i.e. it adds 4 bits to the transmission stream, causing the required delay.
if(fdt_counter == 11'd547) fdt_indicator <= 1'b1; // The ARM must not send earlier to prevent mod_sig_buf overflow.
// The mod_sig_buf can buffer 29 excess data bits, i.e. a maximum delay of 29 * 16 = 464 adc_clk ticks. fdt_indicator
// could appear at ssp_din after 1 tick, 16 ticks for the transfer, 128 ticks until response is sended.
// 1148 - 464 - 1 - 128 - 8 = 547
// for (i = 3; i > 0; i = i - 1)
// begin
// input_shift[i] <= input_shift[i-1];
// end
// input_shift[0] <= adc_d;
input_prev_4 <= input_prev_3;
input_prev_3 <= input_prev_2;
input_prev_2 <= input_prev_1;
input_prev_1 <= adc_d;
end
if ((mod_type == `TAGSIM_MOD) || (mod_type == `TAGSIM_LISTEN))
// assign adc_d_filtered = (input_shift[3] << 1) + input_shift[2] - input_shift[0] - (adc_d << 1);
assign adc_d_filtered = tmp_1 - tmp_2;
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// internal FPGA timing. Maximum required period is 128 carrier clock cycles for a full 8 Bit transfer to ARM. (i.e. we need a
// 7 bit counter). Adjust its frequency to external reader's clock when simulating a tag or sniffing.
reg pre_after_hysteresis;
reg [3:0] reader_falling_edge_time;
reg [6:0] negedge_cnt;
always @(negedge adc_clk)
begin
// detect a reader signal's falling edge and remember its timing:
pre_after_hysteresis <= after_hysteresis;
if (pre_after_hysteresis && ~after_hysteresis)
begin
if(fdt_counter == 11'd1148) // the RF part delays the rising edge by approx 5 adc_clk_ticks, the ADC needs 3 clk_ticks for A/D conversion,
// 16 ticks delay by mod_sig_buf
// 1172 - 5 - 3 - 16 = 1148.
reader_falling_edge_time[3:0] <= negedge_cnt[3:0];
end
// adjust internal timer counter if necessary:
if (negedge_cnt[3:0] == 4'd13 && (mod_type == `SNIFFER || mod_type == `TAGSIM_LISTEN) && deep_modulation)
begin
if (reader_falling_edge_time == 4'd1) // reader signal changes right after sampling. Better sample earlier next time.
begin
if(fdt_elapsed)
begin
if(negedge_cnt[3:0] == mod_sig_flip) mod_sig_coil <= mod_sig; // start modulating (if mod_sig is already set)
sub_carrier_cnt[3:0] <= sub_carrier_cnt[3:0] + 1;
end
negedge_cnt <= negedge_cnt + 2; // time warp
end
else if (reader_falling_edge_time == 4'd0) // reader signal changes right before sampling. Better sample later next time.
begin
negedge_cnt <= negedge_cnt; // freeze time
end
else
begin
negedge_cnt <= negedge_cnt + 1; // Continue as usual
end
reader_falling_edge_time[3:0] <= 4'd8; // adjust only once per detected edge
end
else if (negedge_cnt == 7'd127) // normal operation: count from 0 to 127
begin
negedge_cnt <= 0;
end
else
begin
negedge_cnt <= negedge_cnt + 1;
end
end
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Tag -> PM3:
// determine best possible time for starting/resetting the modulation detector.
reg [3:0] mod_detect_reset_time;
always @(negedge adc_clk)
begin
if (mod_type == `READER_LISTEN)
// (our) reader signal changes at t=1, tag response expected n*16+4 ticks later, further delayed by
// 3 ticks ADC conversion.
// 1 + 4 + 3 = 8
begin
mod_detect_reset_time <= 4'd8;
end
else
if (mod_type == `SNIFFER)
begin
// detect a rising edge of reader's signal and sync modulation detector to the tag's answer:
if (~pre_after_hysteresis && after_hysteresis && deep_modulation)
// reader signal rising edge detected at negedge_cnt[3:0]. This signal had been delayed
// 9 ticks by the RF part + 3 ticks by the A/D converter + 1 tick to assign to after_hysteresis.
// The tag will respond n*16 + 4 ticks later + 3 ticks A/D converter delay.
// - 9 - 3 - 1 + 4 + 3 = -6
begin
mod_detect_reset_time <= negedge_cnt[3:0] - 4'd4;
end
end
end
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Tag -> PM3:
// modulation detector. Looks for the steepest falling and rising edges within a 16 clock period. If there is both a significant
// falling and rising edge (in any order), a modulation is detected.
reg signed [10:0] rx_mod_falling_edge_max;
reg signed [10:0] rx_mod_rising_edge_max;
reg curbit;
always @(negedge adc_clk)
begin
if(negedge_cnt[3:0] == mod_detect_reset_time)
begin
// detect modulation signal: if modulating, there must have been a falling AND a rising edge
if (rx_mod_falling_edge_max > 5 && rx_mod_rising_edge_max > 5)
curbit <= 1'b1; // modulation
else
begin
mod_sig_flip <= negedge_cnt[3:0]; // start modulation at this time
sub_carrier_cnt[3:0] <= 0; // subcarrier phase in sync with start of modulation
mod_sig_coil <= mod_sig; // assign signal to coil
fdt_elapsed = 1'b1;
if(~(| mod_sig_ptr[4:0])) mod_sig_ptr <= 5'd9; // if mod_sig_ptr == 0 -> didn't receive a 1 yet. Delay next 1 by n*128 ticks.
else temp_buffer_reset = 1'b1; // else fix the buffer size at current position
end
end
else
begin
fdt_counter <= fdt_counter + 1; // Count until 1155
end
curbit <= 1'b0; // no modulation
// reset modulation detector
rx_mod_rising_edge_max <= 0;
rx_mod_falling_edge_max <= 0;
end
else // other modes: don't use the delay line.
begin
mod_sig_coil <= ssp_dout;
end
//-------------------------------------------------------------------------------------------------------------------------------------------
// Relevant for READER_LISTEN only
// look for steepest falling and rising edges:
if(negedge_cnt[3:0] == 4'd1) // reset modulation detector. Save current edge.
begin
if (adc_d_filtered > 0)
begin
rx_mod_falling_edge_max <= adc_d_filtered;
rx_mod_rising_edge_max <= 0;
end
else
begin
rx_mod_falling_edge_max <= 0;
rx_mod_rising_edge_max <= -adc_d_filtered;
end
end
else // detect modulation
else // look for steepest edges (slopes)
begin
if (adc_d_filtered > 0)
begin
@ -204,35 +251,279 @@ begin
end
end
// detect modulation signal: if modulating, there must be a falling and a rising edge
if (rx_mod_falling_edge_max > 6 && rx_mod_rising_edge_max > 6)
curbit <= 1'b1; // modulation
end
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Tag+Reader -> PM3
// sample 4 bits reader data and 4 bits tag data for sniffing
reg [3:0] reader_data;
reg [3:0] tag_data;
always @(negedge adc_clk)
begin
if(negedge_cnt[3:0] == 4'd0)
begin
reader_data[3:0] <= {reader_data[2:0], after_hysteresis};
tag_data[3:0] <= {tag_data[2:0], curbit};
end
end
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// PM3 -> Tag:
// a delay line to ensure that we send the (emulated) tag's answer at the correct time according to ISO14443-3
reg [31:0] mod_sig_buf;
reg [4:0] mod_sig_ptr;
reg mod_sig;
always @(negedge adc_clk)
begin
if(negedge_cnt[3:0] == 4'd0) // sample data at rising edge of ssp_clk - ssp_dout changes at the falling edge.
begin
mod_sig_buf[31:2] <= mod_sig_buf[30:1]; // shift
if (~ssp_dout && ~mod_sig_buf[1])
mod_sig_buf[1] <= 1'b0; // delete the correction bit (a single 1 preceded and succeeded by 0)
else
curbit <= 1'b0; // no modulation
mod_sig_buf[1] <= mod_sig_buf[0];
mod_sig_buf[0] <= ssp_dout; // add new data to the delay line
mod_sig = mod_sig_buf[mod_sig_ptr]; // the delayed signal.
end
end
// store previous samples for filtering and edge detection:
adc_d_4 <= adc_d_3;
adc_d_3 <= adc_d_2;
adc_d_2 <= adc_d_1;
adc_d_1 <= adc_d;
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// PM3 -> Tag, internal timing:
// a timer for the 1172 cycles fdt (Frame Delay Time). Start the timer with a rising edge of the reader's signal.
// set fdt_elapsed when we no longer need to delay data. Set fdt_indicator when we can start sending data.
// Note: the FPGA only takes care for the 1172 delay. To achieve an additional 1236-1172=64 ticks delay, the ARM must send
// a correction bit (before the start bit). The correction bit will be coded as 00010000, i.e. it adds 4 bits to the
// transmission stream, causing the required additional delay.
reg [10:0] fdt_counter;
reg fdt_indicator, fdt_elapsed;
reg [3:0] mod_sig_flip;
reg [3:0] sub_carrier_cnt;
// Relevant for TAGSIM_MOD only (timing the Tag's answer. See above)
// When we see end of a modulation and we are emulating a Tag, start fdt_counter.
// Reset fdt_counter when modulation is detected.
if(~after_hysteresis /* && mod_sig_buf_empty */ && mod_type == `TAGSIM_LISTEN)
// we want to achieve a delay of 1172. The RF part already has delayed the reader signals's rising edge
// by 9 ticks, the ADC took 3 ticks and there is always a delay of 32 ticks by the mod_sig_buf. Therefore need to
// count to 1172 - 9 - 3 - 32 = 1128
`define FDT_COUNT 11'd1128
// The ARM must not send too early, otherwise the mod_sig_buf will overflow, therefore signal that we are ready
// with fdt_indicator. The mod_sig_buf can buffer 29 excess data bits, i.e. a maximum delay of 29 * 16 = 464 adc_clk ticks.
// fdt_indicator could appear at ssp_din after 1 tick, the transfer needs 16 ticks, the ARM can send 128 ticks later.
// 1128 - 464 - 1 - 128 - 8 = 535
`define FDT_INDICATOR_COUNT 11'd535
// reset on a pause in listen mode. I.e. the counter starts when the pause is over:
assign fdt_reset = ~after_hysteresis && mod_type == `TAGSIM_LISTEN;
always @(negedge adc_clk)
begin
if (fdt_reset)
begin
fdt_counter <= 11'd0;
fdt_elapsed = 1'b0;
fdt_elapsed <= 1'b0;
fdt_indicator <= 1'b0;
temp_buffer_reset = 1'b0;
mod_sig_ptr <= 5'b00000;
mod_sig = 1'b0;
end
else
begin
if(fdt_counter == `FDT_COUNT)
begin
if(~fdt_elapsed) // just reached fdt.
begin
mod_sig_flip <= negedge_cnt[3:0]; // start modulation at this time
sub_carrier_cnt <= 4'd0; // subcarrier phase in sync with start of modulation
fdt_elapsed <= 1'b1;
end
else
begin
sub_carrier_cnt <= sub_carrier_cnt + 1;
end
end
else
begin
fdt_counter <= fdt_counter + 1;
end
end
if(fdt_counter == `FDT_INDICATOR_COUNT) fdt_indicator <= 1'b1;
end
if(negedge_cnt[3:0] == 4'd1)
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// PM3 -> Reader or Tag
// assign a modulation signal to the antenna. This signal is either a delayed signal (to achieve fdt when sending to a reader)
// or undelayed when sending to a tag
reg mod_sig_coil;
always @(negedge adc_clk)
begin
if (mod_type == `TAGSIM_MOD) // need to take care of proper fdt timing
begin
if(fdt_counter == `FDT_COUNT)
begin
if(fdt_elapsed)
begin
if(negedge_cnt[3:0] == mod_sig_flip) mod_sig_coil <= mod_sig;
end
else
begin
mod_sig_coil <= mod_sig; // just reached fdt. Immediately assign signal to coil
end
end
end
else // other modes: don't delay
begin
mod_sig_coil <= ssp_dout;
end
end
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// PM3 -> Reader
// determine the required delay in the mod_sig_buf (set mod_sig_ptr).
reg temp_buffer_reset;
always @(negedge adc_clk)
begin
if(fdt_reset)
begin
mod_sig_ptr <= 5'd0;
temp_buffer_reset = 1'b0;
end
else
begin
if(fdt_counter == `FDT_COUNT && ~fdt_elapsed) // if we just reached fdt
if(~(| mod_sig_ptr[4:0]))
mod_sig_ptr <= 5'd8; // ... but didn't buffer a 1 yet, delay next 1 by n*128 ticks.
else
temp_buffer_reset = 1'b1; // else no need for further delays.
if(negedge_cnt[3:0] == 4'd0) // at rising edge of ssp_clk - ssp_dout changes at the falling edge.
begin
if((ssp_dout || (| mod_sig_ptr[4:0])) && ~fdt_elapsed) // buffer a 1 (and all subsequent data) until fdt is reached.
if (mod_sig_ptr == 5'd31)
mod_sig_ptr <= 5'd0; // buffer overflow - data loss.
else
mod_sig_ptr <= mod_sig_ptr + 1; // increase buffer (= increase delay by 16 adc_clk ticks). mod_sig_ptr always points ahead of first 1.
else if(fdt_elapsed && ~temp_buffer_reset)
begin
// wait for the next 1 after fdt_elapsed before fixing the delay and starting modulation. This ensures that the response can only happen
// at intervals of 8 * 16 = 128 adc_clk ticks (as defined in ISO14443-3)
if(ssp_dout)
temp_buffer_reset = 1'b1;
if(mod_sig_ptr == 5'd1)
mod_sig_ptr <= 5'd8; // still nothing received, need to go for the next interval
else
mod_sig_ptr <= mod_sig_ptr - 1; // decrease buffer.
end
end
end
end
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// FPGA -> ARM communication:
// buffer 8 bits data to be sent to ARM. Shift them out bit by bit.
reg [7:0] to_arm;
always @(negedge adc_clk)
begin
if (negedge_cnt[5:0] == 6'd63) // fill the buffer
begin
if (mod_type == `SNIFFER)
begin
if(deep_modulation) // a reader is sending (or there's no field at all)
begin
to_arm <= {reader_data[3:0], 4'b0000}; // don't send tag data
end
else
begin
to_arm <= {reader_data[3:0], tag_data[3:0]};
end
end
else
begin
to_arm[7:0] <= {mod_sig_ptr[4:0], mod_sig_flip[3:1]}; // feedback timing information
end
end
if(negedge_cnt[2:0] == 3'b000 && mod_type == `SNIFFER) // shift at double speed
begin
// Don't shift if we just loaded new data, obviously.
if(negedge_cnt[5:0] != 6'd0)
begin
to_arm[7:1] <= to_arm[6:0];
end
end
if(negedge_cnt[3:0] == 4'b0000 && mod_type != `SNIFFER)
begin
// Don't shift if we just loaded new data, obviously.
if(negedge_cnt[6:0] != 7'd0)
begin
to_arm[7:1] <= to_arm[6:0];
end
end
end
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// FPGA -> ARM communication:
// generate a ssp clock and ssp frame signal for the synchronous transfer from/to the ARM
reg ssp_clk;
reg ssp_frame;
reg [2:0] ssp_frame_counter;
always @(negedge adc_clk)
begin
if(mod_type == `SNIFFER)
// SNIFFER mode (ssp_clk = adc_clk / 8, ssp_frame clock = adc_clk / 64)):
begin
if(negedge_cnt[2:0] == 3'd0)
ssp_clk <= 1'b1;
if(negedge_cnt[2:0] == 3'd4)
ssp_clk <= 1'b0;
if(negedge_cnt[5:0] == 6'd0) // ssp_frame rising edge indicates start of frame
ssp_frame <= 1'b1;
if(negedge_cnt[5:0] == 6'd8)
ssp_frame <= 1'b0;
end
else
// all other modes (ssp_clk = adc_clk / 16, ssp_frame clock = adc_clk / 128):
begin
if(negedge_cnt[3:0] == 4'd0)
ssp_clk <= 1'b1;
if(negedge_cnt[3:0] == 4'd8)
ssp_clk <= 1'b0;
if(negedge_cnt[6:0] == 7'd7) // ssp_frame rising edge indicates start of frame
ssp_frame <= 1'b1;
if(negedge_cnt[6:0] == 7'd23)
ssp_frame <= 1'b0;
end
end
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// FPGA -> ARM communication:
// select the data to be sent to ARM
reg bit_to_arm;
reg sendbit;
always @(negedge adc_clk)
begin
if(negedge_cnt[3:0] == 4'd0)
begin
// What do we communicate to the ARM
if(mod_type == `TAGSIM_LISTEN)
@ -248,190 +539,22 @@ begin
end
// check timing of a falling edge in reader signal
if (pre_after_hysteresis && ~after_hysteresis)
reader_falling_edge_time[3:0] <= negedge_cnt[3:0];
// sync clock to external reader's clock:
if (negedge_cnt[3:0] == 4'd13 && (mod_type == `SNIFFER || mod_type == `TAGSIM_MOD || mod_type == `TAGSIM_LISTEN))
begin
// adjust clock if necessary:
if (reader_falling_edge_time < 4'd8 && reader_falling_edge_time > 4'd1)
begin
negedge_cnt <= negedge_cnt; // freeze time
end
else if (reader_falling_edge_time == 4'd8)
begin
negedge_cnt <= negedge_cnt + 1; // the desired state. Advance as usual;
end
else
begin
negedge_cnt[3:0] <= 4'd15; // time warp
end
reader_falling_edge_time <= 4'd8; // only once per detected rising edge
end
//------------------------------------------------------------------------------------------------------------------------------------------
// Prepare 8 Bits to communicate to ARM
if (negedge_cnt == 7'd63)
begin
if (mod_type == `SNIFFER)
begin
if(deep_modulation) // a reader is sending (or there's no field at all)
begin
to_arm <= {after_hysteresis_prev1,after_hysteresis_prev2,after_hysteresis_prev3,after_hysteresis_prev4,1'b0,1'b0,1'b0,1'b0};
end
else
begin
to_arm <= {after_hysteresis_prev1,after_hysteresis_prev2,after_hysteresis_prev3,after_hysteresis_prev4,bit1,bit2,bit3,bit4};
end
negedge_cnt <= 0;
end
else
begin
negedge_cnt <= negedge_cnt + 1;
end
end
else if(negedge_cnt == 7'd127)
begin
if (mod_type == `TAGSIM_MOD)
begin
to_arm[7:0] <= {mod_sig_ptr[4:0], mod_sig_flip[3:1]};
negedge_cnt <= 0;
end
else
begin
to_arm[7:0] <= 8'd0;
negedge_cnt <= negedge_cnt + 1;
end
end
else
begin
negedge_cnt <= negedge_cnt + 1;
end
if(negedge_cnt == 7'd1)
begin
after_hysteresis_prev1 <= after_hysteresis;
bit1 <= curbit;
end
if(negedge_cnt == 7'd17)
begin
after_hysteresis_prev2 <= after_hysteresis;
bit2 <= curbit;
end
if(negedge_cnt == 7'd33)
begin
after_hysteresis_prev3 <= after_hysteresis;
bit3 <= curbit;
end
if(negedge_cnt == 7'd49)
begin
after_hysteresis_prev4 <= after_hysteresis;
bit4 <= curbit;
end
//--------------------------------------------------------------------------------------------------------------------------------------------------------------
// Relevant in TAGSIM_MOD only. Delay-Line to buffer data and send it at the correct time
if(negedge_cnt[3:0] == 4'd0) // at rising edge of ssp_clk - ssp_dout changes at the falling edge.
begin
mod_sig_buf[31:0] <= {mod_sig_buf[30:1], ssp_dout, 1'b0}; // shift in new data starting at mod_sig_buf[1]. mod_sig_buf[0] = 0 always.
// asign the delayed signal to mod_sig, but don't modulate with the correction bit (which is sent as 00010000, all other bits will come with at least 2 consecutive 1s)
// side effect: when ptr = 1 it will cancel the first 1 of every block of ones. Note: this would only be the case if we received a 1 just before fdt_elapsed.
if((ssp_dout || (| mod_sig_ptr[4:0])) && ~fdt_elapsed) // buffer a 1 (and all subsequent data) until fdt_counter = 1148 adc_clk ticks.
//if(mod_sig_ptr == 6'b101110) // buffer overflow at 46 - this would mean data loss
//begin
// mod_sig_ptr <= 6'b000000;
//end
if (mod_sig_ptr == 5'd30) mod_sig_ptr <= 5'd0;
else mod_sig_ptr <= mod_sig_ptr + 1; // increase buffer (= increase delay by 16 adc_clk ticks). ptr always points to first 1.
else if(fdt_elapsed && ~temp_buffer_reset)
// fdt_elapsed. If we didn't receive a 1 yet, ptr will be at 9 and not yet fixed. Otherwise temp_buffer_reset will be 1 already.
begin
// wait for the next 1 after fdt_elapsed before fixing the delay and starting modulation. This ensures that the response can only happen
// at intervals of 8 * 16 = 128 adc_clk ticks intervals (as defined in ISO14443-3)
if(ssp_dout) temp_buffer_reset = 1'b1;
if(mod_sig_ptr == 5'd2) mod_sig_ptr <= 5'd9; // still nothing received, need to go for the next interval
else mod_sig_ptr <= mod_sig_ptr - 1; // decrease buffer.
end
else
begin
if(~mod_sig_buf[mod_sig_ptr-1] && ~mod_sig_buf[mod_sig_ptr+1]) mod_sig = 1'b0;
// finally, assign the delayed signal:
else mod_sig = mod_sig_buf[mod_sig_ptr];
end
end
//-----------------------------------------------------------------------------------------------------------------------------------------------------------------------
// Communication to ARM (SSP Clock and data)
// SNIFFER mode (ssp_clk = adc_clk / 8, ssp_frame clock = adc_clk / 64)):
if(mod_type == `SNIFFER)
begin
if(negedge_cnt[2:0] == 3'b100)
ssp_clk <= 1'b0;
if(negedge_cnt[2:0] == 3'b000)
begin
ssp_clk <= 1'b1;
// Don't shift if we just loaded new data, obviously.
if(negedge_cnt[5:0] != 6'd0)
begin
to_arm[7:1] <= to_arm[6:0];
end
end
if(negedge_cnt[5:4] == 2'b00)
ssp_frame = 1'b1;
else
ssp_frame = 1'b0;
// send sampled reader and tag data:
bit_to_arm = to_arm[7];
else if (mod_type == `TAGSIM_MOD && fdt_elapsed && temp_buffer_reset)
// send timing information:
bit_to_arm = to_arm[7];
end
else
//-----------------------------------------------------------------------------------------------------------------------------------------------------------------------
// Communication to ARM (SSP Clock and data)
// all other modes (ssp_clk = adc_clk / 16, ssp_frame clock = adc_clk / 128):
begin
if(negedge_cnt[3:0] == 4'b1000) ssp_clk <= 1'b0;
// send data or fdt_indicator
bit_to_arm = sendbit;
end
if(negedge_cnt[3:0] == 4'b0111)
begin
// if(ssp_frame_counter == 3'd7) ssp_frame_counter <= 3'd0;
// else ssp_frame_counter <= ssp_frame_counter + 1;
if (negedge_cnt[6:4] == 3'b000) ssp_frame = 1'b1;
else ssp_frame = 1'b0;
end
// ssp_frame = (ssp_frame_counter == 3'd7);
if(negedge_cnt[3:0] == 4'b0000)
begin
ssp_clk <= 1'b1;
// Don't shift if we just loaded new data, obviously.
if(negedge_cnt[6:0] != 7'd0)
begin
to_arm[7:1] <= to_arm[6:0];
end
end
if (mod_type == `TAGSIM_MOD && fdt_elapsed && temp_buffer_reset)
// transmit timing information
bit_to_arm = to_arm[7];
else
// transmit data or fdt_indicator
bit_to_arm = sendbit;
end
end //always @(negedge adc_clk)
assign ssp_din = bit_to_arm;
// Subcarrier (adc_clk/16, for TAGSIM_MOD only).
wire sub_carrier;
assign sub_carrier = ~sub_carrier_cnt[3];