> dirbaio: so I was checking how zephyr does UARTE RX on nRF
> dirbaio: because currently we have the ugly "restart DMA on line idle to flush it" hack
> dirbaio: because according to the docs "For each byte received over the RXD line, an RXDRDY event will be generated. This event is likely to occur before the corresponding data has been transferred to Data RAM."
> dirbaio: so as I understood it, the only way to guarantee the data is actually transferred to RAM is to stop+restart DMA
> dirbaio: well, guess what?
> dirbaio: they just count RXDRDY's, and process that amount of data without restarting DMA
> dirbaio: with a timer configured as counter https://github.com/zephyrproject-rtos/zephyr/blob/main/drivers/serial/uart_nrfx_uarte.c#L650-L692
> dirbaio: 🤔🤷⁉️
> dirbaio: someone saying you can do the "hook up rxdrdy to a counter" trick, someone else saying it's wrong 🤪https://devzone.nordicsemi.com/f/nordic-q-a/28420/uarte-in-circular-mode
So we're going to do just that!
- BufferedUarte is lock-free now. No PeripheralMutex.
- The "restart DMA on line idle to flush it" hack is GONE. This means
- It'll work correctly without RTS/CTS now.
- It'll have better throughput when using RTS/CTS.
The UARTETWISPIn naming is quite horrible. With the nRF53, Nordic realized this
and renamed the interrupts to SERIALn. Let's copy that for our peripheral names, in nrf53 and nrf91.
If the user requests some configuration, but UICR is already programmed
to something else, detect this and warn the user.
We don't do it for the debug port settings, because if they are wrong
then the user will simply not be able to read debug logs.
- APPROTECT enable/disable. Notably this fixes issues with nrf52-rev3 and nrf53 from locking itself at reset.
- Use NFC pins as GPIO.
- Use RESET pin as GPIO.
NFC and RESET pins singletons are made available only when usable as GPIO,
for compile-time checking.
Obtaining the current WDT config is important so that we do not have to duplication configuration around the place. A constructor method has been introduced that returns WDT config in accordance with how the register is presently configured. The bootloader example has also been updated to show the watchdog can be obtained and used.
It's a perfectly fine thing to do, should be just a noop. Erroring is
really annoying when you're writing a payload to uart that might
be zero-length or not.
