RM48L952: What is the maximum output current of a pin if it shorted to the ground

Imre,

The pin drive capabilities are specified in the device datasheets. These range from 2mA up to a maximum of 8mA dependent on which pin it is. Although there is some level of margin on these values, if there is a direct short of a pin to ground and it is driven high, there is potential for permanent damage to the pin and surrounding circuits on the die due to exceeding these max drive specifications. This could, then, also translate to damage to pins near by or internal logic that is near by. I would strongly discourage this type of connection for any length of time without some sort of current limiting circuit in place.

Hi Chunk,

Thank you very much for your answer! I could found the driving strength of 2 to 8mA, depending on a given pin, but what I didn't know it is internally limited or not. Background of my question is that we would like to use two MCUs in a safety related system, where they will communicate with each other’s via SPI. Above this, there will be 4 external ADCs in the design, also connected to both MCUs via SPI. Each ADC is using different SPI interfaces of the MCUs.
So, we will use all the 5 SPI peripherals of the two MCUs. Unfortunately, we have very-very limited room on the PCB, therefore isolating all of the SPI lanes/wires would be impossible.
And, in this case, e.g. if one input pin of an MCU goes to short circuited to ground, because of random HW fault, there is a possibility that it can also damage the other MCU, connected to it, and driving the mentioned pin.
At this moment, I can't see any proper solution for this problem.
Do you have any idea?

Thanks,
Imre

Chunk -> Chuck, I am sorry

Imre,

In this case I would suggest the use of inline resistors for current limiting. i.e., if the pin is driven to 3.6V and shorted to ground, you should be able to utilize an inline resistor to limit the current sourced from the device to ground. This would then protect the device from permanent damage, although it may also prevent proper operation of the SPI signal.

Chuck,

Yes, a series resistor would protect the other MCU. but, as you mentioned, it also makes SPI communication impossible.
This is my problem...
Do you know what is the absolute maximum output current of a pin (without suffering physical damage)?
I guess it is higher than the current level, noted as" output strength".
And I also guess, that is not the "maximum clamp current" neither (written in the datasheet).
Do you have any suggestion?

Thanks,
Imre