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updated conditions for stopping the detection of a double listen window

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tharexde 2020-06-29 00:01:19 +02:00
parent 8854c7b688
commit 3f70f1154b
1 changed files with 5 additions and 4 deletions
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9
armsrc/em4x50.c
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@ -74,7 +74,7 @@ static em4x50_tag_t tag = {
#define EM4X50_T_TAG_FULL_PERIOD 64
#define EM4X50_T_TAG_TPP 64
#define EM4X50_T_TAG_TWA 64
#define EM4X50_T_WAITING_FOR_LIW 8 // determined empiracally
#define EM4X50_T_WAITING_FOR_DBLLIW 1600
#define EM4X50_TAG_TOLERANCE 8
#define EM4X50_TAG_WORD 45
@ -424,12 +424,13 @@ static bool find_double_listen_window(bool bcommand) {
// find two successive listen windows that indicate the beginning of
// data transmission
// listen windows should be detected within T0 * EM4X50_T_WAITING_FOR_LIW
// pulses (empirically determined)
// double listen window to be detected within 1600 pulses -> worst case
// reason: first detectable double listen window after 34 words
// -> 34 words + 34 single listen windows -> about 1600 pulses
int cnt_pulses = 0;
while (cnt_pulses < T0 * EM4X50_T_WAITING_FOR_LIW) {
while (cnt_pulses < EM4X50_T_WAITING_FOR_DBLLIW) {
// identification of listen window is done via evaluation of
// pulse lengths