I am writing to request assistance regarding an issue with your SC18IS604PWU SPI-to-I2C converter.
The core problem is that the converter is not asserting the interrupt signal from the I2C_INT pin, even after being properly initialized via the SPI bus. Consequently, our DSP is not triggered to initiate I2C communication.
I have performed the following troubleshooting steps:
Software Verification: I am using the exact same firmware that operates correctly on an older, functional version of our board, where the converter generates the interrupt signal as expected.
Hardware Inspection (New Board):
Continuity Check: I have verified the continuity of all SPI and interrupt signal traces with a multimeter. All connections are sound.
Signal Measurement: Using an oscilloscope, I have probed the I2C_INT pin directly on the converter and observed no activity whatsoever (no falling edge).
Input Signals: I have confirmed that the VCC and RESET pins of the converter are operating correctly. I have also verified that the incoming SPI signals (SCLK, MOSI, and CS) are present and correct, matching the signals on the working board.
Since the component functions correctly on an older board with the same software, but fails on a new board despite extensive hardware verification, I suspect a potential component manufacturing issue or a subtle timing-related problem that is not immediately apparent.
I can provide the relevant schematics and oscilloscope captures of the working board's operation if necessary.
Any guidance you can provide to help resolve this issue would be greatly appreciated.
