SLLA640 April   2025 ISO1228

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1ISO1228 - Relevant Device Information
  5. 2Parallel and Serial Output Modes
  6. 3Switching Communication Modes During Operation
    1. 3.1 Parallel to Serial
    2. 3.2 Serial to Parallel
  7. 4SPI Functional Modes
    1. 4.1 Normal Mode
      1. 4.1.1 Normal Mode - Read IN8-IN1 Continuously
    2. 4.2 Burst Mode
  8. 5Maximum Data Throughput in Serial Mode
  9. 6Digital Low Pass Filtering of Outputs
  10. 7Summary
  11. 8References

3.2 Serial to Parallel

A serial to parallel mode transition needs to be executed as shown in the following when starting in serial mode (COMM_SEL = 1):

  1. Make sure that all MCU pins connected to the output pins of the ISO1228 (pins 35 to 28) are tristated.
  2. Set COMM_SEL = 0 to transition to parallel mode.
  3. Wait for minimum 50ns to allow I/O buffers to change from SPI mode to parallel output mode cleanly
  4. ISO1228 is now in parallel mode

The state of OUTx pins are undetermined during the 50ns transition period and need to be ignored. Any register configuration done while in serial mode is retained when switching to parallel mode until the device is power cycled.