Closed busyrock closed 3 years ago
Hi Busyrock, I think it's a typo and should be "SDO". A search in the datasheet only returns 1 result for "SPO". The ams.com website seems to be very very slow, so I can't check if there's a new datasheet available. By the way, I didn't develop the AS3933 solution further. Bluetooth low energy seemed a much better alternative to me.
Dear Christoph, AS3933 has a wakeup protocol of Frequency Detection Only.
In this section, as3933 should receive data after the Carrier Burst siginal. When the Manchester decoder is enabled (R1<3>=1), the AS3933 decodes the incoming Manchester bits automatically and the Manchester decoded data are displayed on the DAT pin and the Manchester recovered clock on the CL_DAT.
But in practice the CL_DAT PIN does not display recovered clock signal after wakeup. In case a Manchester timing violation happens, the signal on SPO goes high for a duration of 4 periods of internal clock. But I do not find SPO PIN on the AS3933 chip.
Could you give me some advice? Thank you for consultation.