7.3.8 Interrupt Pin (INTB)
The INTB pin is an active low interrupt output pin that acts as an interrupt for various local and remote interrupt conditions (see registers 0xC6 and 0xC7 of Register Maps). For the remote interrupt condition, the INTB pin works in conjunction with the INTB_IN pin on the deserializer. This interrupt signal, when configured, will propagate from the deserializer to the serializer.
- On the Serializer, set register 0xC6 = 1 and 0xC6 = 1
- Deserializer INTB_IN pin is set LOW by some downstream device.
- Serializer pulls INTB pin LOW. The signal is active LOW, so a LOW indicates an interrupt condition.
- External controller detects INTB = LOW; to determine interrupt source, read ISR register.
- A read to ISR will clear the interrupt at the Serializer, releasing INTB.
- The external controller typically must then access the remote device to determine downstream interrupt source and clear the interrupt driving the Deserializer INTB_IN. This would be when the downstream device releases the INTB_IN pin on the Deserializer. The system is now ready to return to step (2) at next falling edge of INTB_IN.