how read parallel 8 bits data in pins and write to RAM the fastest?

RE: how read parallel 8 bits data in pins and write to RAM the fastest?

ovrebekk — Tue, 06 Mar 2018 09:51:58 GMT

Shift operations, as well as integer arithmetic operations, all run in a single clock cycle.

This assumes that the data you want to shift is located in a register, so you have to take into account the time needed to move the data into the register first.

Best regards
Torbjørn

RE: how read parallel 8 bits data in pins and write to RAM the fastest?

chenlmm — Thu, 01 Mar 2018 02:37:22 GMT

How long is shifting 1bit operation ? I want catch the data from GPIO's 8bits ,when another gpio input signal (8Mhz) rise edge come.Can you get me an code or help ?

RE: how read parallel 8 bits data in pins and write to RAM the fastest?

chenlmm — Tue, 26 Sep 2017 08:06:24 GMT

I have getted the answer,thanks!

RE: how read parallel 8 bits data in pins and write to RAM the fastest?

RK — Tue, 26 Sep 2017 06:23:52 GMT

on the nRF52832 you can't read the peripheral in one CPU clock. The APB runs at 16MHz and reads always stall the processor to wait for the bus.

You basically asked this question yesterday and you can't do what you want. You can't read 16MHz parallel data into the chip, not via DMA, not via clever code, not via assembly. As was pointed out yesterday as well, there's nowhere near enough resources to hold that amount of data, all the memory in the entire chip could contain just over 10ms of data at that rate and that's if nothing else was using memory. Nor could you send anything like that amount of data over bluetooth.

So if you really need to interface with a chip churning out 16MHz 8 bit parallel data, you are trying to do it using the wrong ic, the nRF is designed for low power bluetooth operation.

RE: how read parallel 8 bits data in pins and write to RAM the fastest?

Nguyen Hoan Hoang — Tue, 26 Sep 2017 03:49:42 GMT

This is the fastest way but not in 1 clock, not even if you write it in assembly.

uint32_t x = NRF_GPIO->IN;