pad assignment

[Beau R.]

I've been going back and forth with my manager, and I need source to show whether I'm right or wrong about a specific possible functionality of the nRF51.

I was wondering whether you can change the pad assignment.

For example, can I set pad A7 that is normally set to pin0.26/AIN0/XL2 to map to pin0.21 .

I'm pretty sure that you can't. I believe he is mixing up the concept of mapping SPI/TWI/PWM/... (a peripheral module) to a pin(s) which is(/are) mapped to a static pad.

Any clarifications would be greatly appreciated to settle this issue. Thanks.

[RK]

You are correct. For I/O purposes, a given pad has a fixed gpio. There wouldn't be much point in allowing arbitrary gpio/pad muxing, if you want to use pin X then you write to the GPIO for X, if you change to pin Y, then you just fix your code to use the GPIO for Y. I can think of a couple of use cases for wanting arbitrary pin muxing, but they are pretty abstract.

So indeed he probably is mixing up mapping the peripherals to given pins, which is possible and is very useful.

Just reading the nRF51822 reference documentation shows the fixed GPIO/pad mapping, also showing the pins which are dual use (like the clock pins and the fixed ADC inputs). That's about as close as you can get to proving a negative.

[Beau R.]

thank you.