Is there any way we can output hi & lo voltage with an array by PPI?

[min_yuan]

Hi,

I want to output a high & low voltage with an array, the array contains a sequence number, looks like: {0, 1, 0, 0, 0, 1, 1, 1, 1, 0, ...} , and the length of the array is fixed, might be 100, I know I can using the GPIO and a while loop to do that, but I want to do it without CPU, because the interval of each voltage needs less 1us, e.g every 120ns output a high or low.

I know how to use PPI, Timer, GPIO&GPIOTE, but no idea how to combine them, to take an element from the array, and put it as the output of the GPIO PIN.

Thanks

[Håkon Alseth]

Hi,

 

I want to output a high & low voltage with an array, the array contains a sequence number, looks like: {0, 1, 0, 0, 0, 1, 1, 1, 1, 0, ...}

Unfortunately, you cannot output such a sequence with PPI and GPIOTE. You can output simpler things like toggling a GPIO based on timer input, but not actual sequences like that.

You could use SPIM peripheral for this purpose by clocking out the specific byte pattern on MOSI.

 

Kind regards,

Håkon 

[min_yuan]

Hi there! thanks for your reply, yeah, finally, I used and I2C to talk with and external DAC to output high & low voltage.

[Håkon Alseth]

Glad to hear that you found a solution! Hope you have a good weekend!

[min_yuan]

Hi Håkon , 

the speed of the i2c way is not enough, I'm wonder is there any way I can update the CC register by PPI, so I can control the toggling interval of the GPIO, to simulate the HI & LOG output by array.

[Håkon Alseth]

Hi,

 

No, PPI cannot update a timer CC register, it can only route tasks and events together.

I'd recommend that you try the SPIM peripheral if the I2C wasn't fast enough.

 

Kind regards,

Håkon