github/RRG-Proxmark3
1
0
Fork 0
mirror of https://github.com/RfidResearchGroup/proxmark3.git synced 2025-08-20 21:33:47 -07:00
Code Issues Projects Releases Packages Wiki Activity Actions 4

updated conditions for stopping the detection of a double listen window

Browse source
This commit is contained in:
tharexde 2020-06-29 00:01:19 +02:00
commit 3f70f1154b
1 changed files with 5 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

9
armsrc/em4x50.c
View file

@ -74,7 +74,7 @@ static em4x50_tag_t tag = {
#define EM4X50_T_TAG_FULL_PERIOD 64 #define EM4X50_T_TAG_FULL_PERIOD 64
#define EM4X50_T_TAG_TPP 64 #define EM4X50_T_TAG_TPP 64
#define EM4X50_T_TAG_TWA 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_TOLERANCE 8
#define EM4X50_TAG_WORD 45 #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 // find two successive listen windows that indicate the beginning of
// data transmission // data transmission
// listen windows should be detected within T0 * EM4X50_T_WAITING_FOR_LIW // double listen window to be detected within 1600 pulses -> worst case
// pulses (empirically determined) // reason: first detectable double listen window after 34 words
// -> 34 words + 34 single listen windows -> about 1600 pulses
int cnt_pulses = 0; 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 // identification of listen window is done via evaluation of
// pulse lengths // pulse lengths