//-----------------------------------------------------------------------------
// Iceman, July 2018
// edits by - Anticat, August 2018
//
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// The main USART code, for serial communications over FPC connector
//-----------------------------------------------------------------------------
#include "cmd.h"
#include "usart.h"
#include "string.h"
#include "../armsrc/ticks.h" // startcountus
volatile AT91PS_USART pUS1 = AT91C_BASE_US1;
volatile AT91PS_PIO pPIO = AT91C_BASE_PIOA;
volatile AT91PS_PDC pPDC = AT91C_BASE_PDC_US1;
uint32_t usart_baudrate = 0;
uint8_t usart_parity = 0;
/*
void usart_close(void) {
// Reset the USART mode
pUS1->US_MR = 0;
// Reset the baud rate divisor register
pUS1->US_BRGR = 0;
// Reset the Timeguard Register
pUS1->US_TTGR = 0;
// Disable all interrupts
pUS1->US_IDR = 0xFFFFFFFF;
// Abort the Peripheral Data Transfers
pUS1->US_PTCR = AT91C_PDC_RXTDIS | AT91C_PDC_TXTDIS;
// Disable receiver and transmitter and stop any activity immediately
pUS1->US_CR = AT91C_US_TXDIS | AT91C_US_RXDIS | AT91C_US_RSTTX | AT91C_US_RSTRX;
}
*/
static uint8_t us_inbuf1[USART_BUFFLEN];
static uint8_t us_inbuf2[USART_BUFFLEN];
uint8_t *usart_cur_inbuf = NULL;
uint16_t usart_cur_inbuf_off = 0;
static uint8_t us_rxfifo[USART_FIFOLEN];
static size_t us_rxfifo_low = 0;
static size_t us_rxfifo_high = 0;
static void usart_fill_rxfifo(void) {
uint16_t rxfifo_free = 0;
if (pUS1->US_RNCR == 0) { // One buffer got filled, backup buffer being used
if (us_rxfifo_low > us_rxfifo_high)
rxfifo_free = us_rxfifo_low - us_rxfifo_high;
else
rxfifo_free = sizeof(us_rxfifo) - us_rxfifo_high + us_rxfifo_low;
uint16_t available = USART_BUFFLEN - usart_cur_inbuf_off;
if (available <= rxfifo_free) {
for (uint16_t i = 0; i < available; i++) {
us_rxfifo[us_rxfifo_high++] = usart_cur_inbuf[usart_cur_inbuf_off + i];
if (us_rxfifo_high == sizeof(us_rxfifo))
us_rxfifo_high = 0;
}
// Give next buffer
pUS1->US_RNPR = (uint32_t)usart_cur_inbuf;
pUS1->US_RNCR = USART_BUFFLEN;
// Swap current buff
if (usart_cur_inbuf == us_inbuf1)
usart_cur_inbuf = us_inbuf2;
else
usart_cur_inbuf = us_inbuf1;
usart_cur_inbuf_off = 0;
} else {
// Take only what we have room for
available = rxfifo_free;
for (uint16_t i = 0; i < available; i++) {
us_rxfifo[us_rxfifo_high++] = usart_cur_inbuf[usart_cur_inbuf_off + i];
if (us_rxfifo_high == sizeof(us_rxfifo))
us_rxfifo_high = 0;
}
usart_cur_inbuf_off += available;
return;
}
}
if (pUS1->US_RCR < USART_BUFFLEN - usart_cur_inbuf_off) { // Current buffer partially filled
if (us_rxfifo_low > us_rxfifo_high)
rxfifo_free = us_rxfifo_low - us_rxfifo_high;
else
rxfifo_free = sizeof(us_rxfifo) - us_rxfifo_high + us_rxfifo_low;
uint16_t available = USART_BUFFLEN - pUS1->US_RCR - usart_cur_inbuf_off;
if (available > rxfifo_free)
available = rxfifo_free;
for (uint16_t i = 0; i < available; i++) {
us_rxfifo[us_rxfifo_high++] = usart_cur_inbuf[usart_cur_inbuf_off + i];
if (us_rxfifo_high == sizeof(us_rxfifo))
us_rxfifo_high = 0;
}
usart_cur_inbuf_off += available;
}
}
uint16_t usart_rxdata_available(void) {
usart_fill_rxfifo();
if (us_rxfifo_low <= us_rxfifo_high)
return us_rxfifo_high - us_rxfifo_low;
else
return sizeof(us_rxfifo) - us_rxfifo_low + us_rxfifo_high;
}
uint32_t usart_read_ng(uint8_t *data, size_t len) {
if (len == 0) return 0;
uint32_t nbBytesRcv = 0;
uint32_t try = 0;
// uint32_t highest_observed_try = 0;
// Empirical max try observed: 3000000 / USART_BAUD_RATE
// Let's take 10x
uint32_t tryconstant = 0;
#ifdef USART_SLOW_LINK
// Experienced up to 13200 tries on BT link even at 460800
tryconstant = 50000;
#endif
uint32_t maxtry = 10 * (3000000 / USART_BAUD_RATE) + tryconstant;
while (len) {
uint32_t available = usart_rxdata_available();
uint32_t packetSize = MIN(available, len);
if (available > 0) {
// Dbprintf_usb("Dbg USART ask %d bytes, available %d bytes, packetsize %d bytes", len, available, packetSize);
// highest_observed_try = MAX(highest_observed_try, try);
try = 0;
}
len -= packetSize;
while (packetSize--) {
data[nbBytesRcv++] = us_rxfifo[us_rxfifo_low++];
if (us_rxfifo_low == sizeof(us_rxfifo))
us_rxfifo_low = 0;
}
if (try++ == maxtry) {
// Dbprintf_usb("Dbg USART TIMEOUT");
break;
}
}
// highest_observed_try = MAX(highest_observed_try, try);
// Dbprintf_usb("Dbg USART max observed try %i", highest_observed_try);
return nbBytesRcv;
}
// transfer from device to client
inline int usart_writebuffer_sync(uint8_t *data, size_t len) {
// Wait for current PDC bank to be free
// (and check next bank too, in case there will be a usart_writebuffer_async)
while (pUS1->US_TNCR || pUS1->US_TCR) {};
pUS1->US_TPR = (uint32_t)data;
pUS1->US_TCR = len;
// Wait until finishing all transfers to make sure "data" buffer can be discarded
// (if we don't wait here, bulk send as e.g. "hw status" will fail)
while (pUS1->US_TNCR || pUS1->US_TCR) {};
return PM3_SUCCESS;
}
void usart_init(uint32_t baudrate, uint8_t parity) {
if (baudrate != 0)
usart_baudrate = baudrate;
if ((parity == 'N') || (parity == 'O') || (parity == 'E'))
usart_parity = parity;
// For a nice detailed sample, interrupt driven but still relevant.
// See https://www.sparkfun.com/datasheets/DevTools/SAM7/at91sam7%20serial%20communications.pdf
// disable & reset receiver / transmitter for configuration
pUS1->US_CR = (AT91C_US_RSTRX | AT91C_US_RSTTX | AT91C_US_RXDIS | AT91C_US_TXDIS);
//enable the USART1 Peripheral clock
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_US1);
// disable PIO control of receive / transmit pins
pPIO->PIO_PDR |= (AT91C_PA21_RXD1 | AT91C_PA22_TXD1);
// enable peripheral mode A on receive / transmit pins
pPIO->PIO_ASR |= (AT91C_PA21_RXD1 | AT91C_PA22_TXD1);
pPIO->PIO_BSR = 0;
// enable pull-up on receive / transmit pins (see 31.5.1 I/O Lines)
pPIO->PIO_PPUER |= (AT91C_PA21_RXD1 | AT91C_PA22_TXD1);
// set mode
uint32_t mode = AT91C_US_USMODE_NORMAL | // normal mode
AT91C_US_CLKS_CLOCK | // MCK (48MHz)
AT91C_US_OVER | // oversampling
AT91C_US_CHRL_8_BITS | // 8 bits
AT91C_US_NBSTOP_1_BIT | // 1 stop bit
AT91C_US_CHMODE_NORMAL; // channel mode: normal
switch (usart_parity) {
case 'N':
mode |= AT91C_US_PAR_NONE; // parity: none
break;
case 'O':
mode |= AT91C_US_PAR_ODD; // parity: odd
break;
case 'E':
mode |= AT91C_US_PAR_EVEN; // parity: even
break;
}
pUS1->US_MR = mode;
// all interrupts disabled
pUS1->US_IDR = 0xFFFF;
// http://ww1.microchip.com/downloads/en/DeviceDoc/doc6175.pdf
// note that for very large baudrates, error is not neglectible:
// b921600 => 8.6%
// b1382400 => 8.6%
// FP, Fractional Part (Datasheet p402, Supported in AT91SAM512 / 256) (31.6.1.3)
// FP = 0 disabled;
// FP = 1-7 Baudrate resolution,
// CD, Clock divider,
// sync == 0 , (async?)
// OVER = 0, -no
// baudrate == selected clock/16/CD
// OVER = 1, -yes we are oversampling
// baudrate == selected clock/8/CD --> this is ours
//
uint32_t brgr = 48000000 / (usart_baudrate << 3);
// doing fp = round((mck / (usart_baudrate << 3) - brgr) * 8) with integers:
uint32_t fp = ((16 * 48000000 / (usart_baudrate << 3) - 16 * brgr) + 1) / 2;
pUS1->US_BRGR = (fp << 16) | brgr;
// Write the Timeguard Register
pUS1->US_TTGR = 0;
pUS1->US_RTOR = 0;
pUS1->US_FIDI = 0;
pUS1->US_IF = 0;
// Initialize DMA buffers
pUS1->US_TPR = (uint32_t)0;
pUS1->US_TCR = 0;
pUS1->US_TNPR = (uint32_t)0;
pUS1->US_TNCR = 0;
pUS1->US_RPR = (uint32_t)us_inbuf1;
pUS1->US_RCR = USART_BUFFLEN;
usart_cur_inbuf = us_inbuf1;
usart_cur_inbuf_off = 0;
pUS1->US_RNPR = (uint32_t)us_inbuf2;
pUS1->US_RNCR = USART_BUFFLEN;
// Initialize our fifo
us_rxfifo_low = 0;
us_rxfifo_high = 0;
// re-enable receiver / transmitter
pUS1->US_CR = (AT91C_US_RXEN | AT91C_US_TXEN);
// ready to receive and transmit
pUS1->US_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
}