Hi Ben,
SOF is detected when a 12 bit pattern 0xF0A is transmitted on ser_data. So if you are assuming SOF to be a wire input, that means we need to write a separate logic (a pattern detector- 12 bit shift reg and a decoder?) to detect 0xFOA pattern on the ser_data and generate SOF which is input to property. Also we need to detect EOF in a similar fashion. Since SOF and EOF patterns are identical, we will need some additional logic to detect EOF (the first 0xFOA pattern after reset is SOF and 0xFOA pattern received after SOF is EOF. )
The problem with above approach is that the SOF input will go high AFTER 0xFOA(12’b111100001010) pattern is detected. So the SOF output will go high after last 1010 pattern (data is sent MSB first). But the ser_data should be zero only till first nibble F is received. So we cannot use until.
regards,
-sunil