How to use send and receive serial data over gpio pins?

RE: How to use send and receive serial data over gpio pins?

Jørgen Holmefjord — Fri, 01 Nov 2019 15:42:07 GMT

Software serial requires the CPU to be available to read/write the GPIOs at the exact time that the bits are received. In a single-core BLE SoC like the nRF51, the CPU will always have highest priority to handle timing-critical events. The UART peripheral in nRF51 series ICs has a built-in HW FIFO that allows you to receive up to 6 bytes without CPU intervention.

You may be able to do those low baudrates with bit-banging/software serial, but there is no guarantee that it will work. I would rather recommend using the HW UART peripheral for supported baudrates.

RE: How to use send and receive serial data over gpio pins?

daverv — Wed, 30 Oct 2019 18:00:19 GMT

Hi,

Is there any particular reason why not to use SoftwareSerial ?

I'm trying to establish two way communications between an nrf51 and an arduino using software serial and uart.

What I'm seeing is that I send 20 bytes from arduino but the nrf51 doesn't receive them all. And if I sent only one byte from arduino, the nrf51 seams to receive 4 bytes.

If I send 20 bytes from nrf51 to arduino, arduino receives them well, but not the other way around.

Edit: I've tried this with 1200, 2400 and 9600 baud rates.

RE: How to use send and receive serial data over gpio pins?

Jørgen Holmefjord — Mon, 03 Sep 2018 09:24:03 GMT

Hi,

Is there any specific reasons you want to use software serial? The UART peripheral of nRF51 series support baudrates of 9600 (and lower). Please have a look at the reference manual.

Best regards.
Jørgen