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chg cotag operates on 132kHz. textual

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iceman1001 2019-10-10 10:34:56 +02:00
commit 49caa7f962
1 changed files with 27 additions and 8 deletions
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35
armsrc/lfops.c
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@ -2411,18 +2411,37 @@ void EM4xWriteWord(uint8_t addr, uint32_t data, uint32_t pwd, uint8_t usepwd) {
}
/*
Reading a COTAG.
Reading COTAG.
COTAG needs the reader to send a startsequence and the card has an extreme slow datarate.
because of this, we can "sample" the data signal but we interpreate it to Manchester direct.
READER START SEQUENCE:
burst 800 us, gap 2.2 msecs
burst 3.6 msecs gap 2.2 msecs
burst 800 us gap 2.2 msecs
pulse 3.6 msecs
This behavior looks very similar to old ancient Motorola Flexpass
-----------------------------------------------------------------------
According to patent:
Operating freq
reader 132 kHz
tag 66 kHz
Divide by 384 counter
PULSE repetition 5.82ms
LOW 2.91 ms
HIGH 2.91 ms
Also references to a half-bit format and leading zero.
-----------------------------------------------------------------------
READER START SEQUENCE:
burst 800 us gap 2.2 ms
burst 3.6 ms gap 2.2 ms
burst 800 us gap 2.2 ms
pulse 3.6 ms
This triggers COTAG tag to response
This triggers a COTAG tag to response
*/
void Cotag(uint32_t arg0) {
#ifndef OFF
@ -2435,7 +2454,7 @@ void Cotag(uint32_t arg0) {
LED_A_ON();
LFSetupFPGAForADC(LF_DIVISOR_134, true);
LFSetupFPGAForADC(LF_DIVISOR(132), true);
//clear buffer now so it does not interfere with timing later
BigBuf_Clear_ext(false);