Hi team,
My customer is working with SN65HVD88 (+ SN65HVD3082) and I have several questions relating to polarity correction feature. Would you mind helping me with them?
1) The polarity-correcting mode is entered only when VID < -100mV and t > 76ms and DE = low. Is my understanding right?
2) Is the polarity-correcting only enabled after each power-up or will it repeat if the above three conditions are valid during normal operation?
3) About the fail-safe resistor value selection, if the VID needs to < -100mv to enable the polarity-correcting in idle state, why Table 3of the datasheet lists sets of combination that is not? eg. 13mV, 29mV.. I'm confused..
4) My customer has used a termination resistor- 120ohm and 1K/1K fail-safe in SN65HVD3082 (host) side but no termination at SN65HVD888 (slave) side. And is fail-safe resistor value OK?
5) From my understanding of 888's correction scheme, I would like to raise another way to enable polarity correction and can you check if I'm right?
If the SN65HVD3082 (host) initially pulls DE high, and D to be H after power up, it gives the BUS a solid differentiated state for the SN65HVD888 to recognize. 76ms later, SN65HVD888 should be able to correct the polarity if reversed. Is that right? If yes, any potential risks?
Please help review my questions above and thanks in advance.
Regards,
Patrick