Hi team,
Here's an issue from the customer may need your help:
Customers do not have a development board for the MCT8316A, so debug the custom MCT8316A with the EVM board for the MSP430 monolithic in the MCT8316A EVM as shown in the figure above.
And they have a problem when debugging: the pull-up resistance of the IIC bus is soldered to the 430 monolithic development board. If the custom 8316 board is powered before connecting the USB cable between the 430 monolithic device and the PC, the serial transceiver indicator flashes periodically when the upper computer is connected. It's verified that the communication between the official GUI and the 430 monolithic device is good, but once the 8316 register is read and written by the upper computer, the connection is indicated as shown in the following figure:
The power-up sequence can only be reversed(this is the only way they could try) by connecting the USB cable between the 430 monolithic development board and the PC before powering the custom 8316 board. All subsequent reads and writes will work.
The difference between these two operations is:
If the custom 8316 board is powered on first, then the 8316 does power up, but its IIC is not pulled up, and both SCK and SDA are actually tested at 0V; If the 430 development board is powered first, the IIC bus is pulled to 3.3 V before powering on the custom 8316 development board, leaving the bus in a normal idle state.
The customer is wondering if you can help verify the following case: regarding MCT8316A and MCF8316, if SCK and SDA were in an abnormal state before the chip was powered, for example, since no pull-up results in both signals being 0 V, is this a bus exception state considered and recorded internally in the 8316, resulting in an exception in communication between the upper computer and it?
Could you please help check this case? Thanks.
Best Regards,
Cherry
