Dear TI, my question is concerning the SN65HVD888 and its ability to auto polarity correct.
Per the spec, for the SN65HVD888 to detect and do bus polarity correction, the following 3 condition must be met:
• A failsafe-biasing network (commonly at the master node) must define the signal polarity of the bus
• A slave node must enable the receiver and disable the driver (RE = DE = Low)
• The bus must idle for the failsafe time, tFS-max
Based on the above;
1. How is the above process affected by powering the device up?
2. Do those 3 conditions always allow the device to perform bus polarity correction, even if the device has already latched in a polarity correcting event.
3. Can the polarity correcting event be done over and over again as long as the device is powered on and the above 3 conditions are met?
4. Without a power up cycle, will the SN65HVD888 perform polarity correction when the above conditions met, even if the source of the failsafe-biasing network is hot-swapped on the fly?
What I want to achieve is the ability to allow a main computer with a SN65HVD888 to auto correct polarity whenever a new failsafe-biasing 485 driver is hot-swapped on to the network.
Is the above possible and if so, what issues could interfere with functionality?
Thx
Jeff Boyer | Director Of Engineering | TekMagic
M: +1-484-364-8351
Email: Jeff.B@TekMagic.net
