Dear sir or madam
We are using the TRF7960 for many years.
Accidentally we stumbled upon an issue regarding the default TX modulation pulse length in ISO14443A mode (Bit rate 106 kbps).
The datasheet states, that the preset for ISO14443A with 106 kbps is 2.36 µs (Table 5-16 TX Pulse Length Control). But in contrast we measured a TX pulse length of only ~1,2 µs, which is theoretically way to short compared to the definition in ISO14443 standard, which defines a pulse length not less than 2 µs.
Selecting a pulse length of ~ 2,36 µs "manually" by writing 20h to TX Pulse Length Control register 06h results in a correct measured pulse length of ~ 2.35 µs.
So obviously the preset value seems to be not correct.
Anyhow we never encountered any problems with any ISO 14443A Tags when using the preset and therefore the short pulse length.
But we still wonder, if this is a known issue for the TRF7960.
Maybe you can shed some light on this observation.
Best regards
Burkhard Bröhl