Hi, Following this thread, I better understand the problems I had when I tried to port RIOT on Arduino/Genuino Zero in [1]. I'll test your changes in cpu/samd21/periph/uart.c to see if they fix them. Note that it uses an Atmel ATSAMD21G18 MCU which is again another variant of samd21.
Alex [1] https://github.com/RIOT-OS/RIOT/pull/5475 ----- Mail original ----- > As promissed ... > > The final change to make it work was selecting the correct "mux". There > were a few hardcoded things in > * boards/samr21-xpro/include/periph_conf.h > * cpu/samd21/periph/uart.c > > SAMR21_XPRO has the first serial connected to: > RX - PA5 > TX - PA4 > static const uart_conf_t uart_config[] = { > /* device, RX pin, TX pin, mux */ > {&SERCOM0->USART, GPIO_PIN(PA,5), GPIO_PIN(PA,4), GPIO_MUX_D}, > > > My SODAQ Autonomo board has the first serial connected to: > RX - PA9 > TX - PA10 > static const uart_conf_t uart_config[] = { > /* device, RX pin, TX pin, mux */ > {&SERCOM0->USART, GPIO_PIN(PA,9), GPIO_PIN(PA,10), GPIO_MUX_C}, > > Is that all? No, welcome to the SERCOM world of ARM Cortex M0. > In cpu/sam???/periph/uart.c some changes are needed too. In the next > diff, the samr21 > is the "old" samd21. > > --- cpu/samd21/periph/uart.c 2016-06-13 22:41:15.358773522 +0200 > +++ cpu/samr21/periph/uart.c 2016-05-31 19:57:02.788554067 +0200 > @@ -86,10 +86,9 @@ > /* reset the UART device */ > dev->CTRLA.reg = SERCOM_USART_CTRLA_SWRST; > while (dev->SYNCBUSY.reg & SERCOM_USART_SYNCBUSY_SWRST) {} > - /* set asynchronous mode w/o parity, LSB first, PAD2 to TX, PAD1 to > RX, sample rate 16x and > + /* set asynchronous mode w/o parity, LSB first, PAD0 to TX, PAD1 to > RX and > * use internal clock */ > dev->CTRLA.reg = (SERCOM_USART_CTRLA_DORD | > - SERCOM_USART_CTRLA_TXPO(0x1) | > SERCOM_USART_CTRLA_RXPO(0x1) | > SERCOM_USART_CTRLA_SAMPR(0x1) | > SERCOM_USART_CTRLA_MODE_USART_INT_CLK); > > > Notice the TXPO and RXPO. These indicate which "pads" the pin can use on > a certain SERCOM. > So, what we can learn from this is that we need to expand uart_conf_t. > We need PAD configuration > too. (BTW, Arduino Core is doing similar things.) > > Was this a TL;DR? Sorry about it then. > -- Kees > > > On 13-06-16 23:28, Peter Kietzmann wrote: > > Congrats! Looking forward to hear the trick that did it :-). > > > > Good night > > Peter > > > > Am 13.06.2016 um 23:21 schrieb Kees Bakker: > >> On 13-06-16 20:55, Kees Bakker wrote: > >>> > >>> That is more or less already what I did. I filled in uart_config[] > >>> with two devices > >>> and I have a serial line connect to my PC. This configuration works > >>> with the Arduino > >>> setup. But not yet with RIOT. > >> > >> I almost gave up ..., but then ... > >> > >> �main(): This is RIOT! (Version: > >> 2016.07-devel-191-g42127-rapper-sodaq-autonomo) > >> Hello World! > >> You are running RIOT on a(n) sodaq-autonomo board. > >> This board features a(n) samd21 MCU. > >> > >> Yeah, it's working. Well, hello world is. > >> (( It's getting too late now. I'll explain later this week what was > >> needed to make it work. )) > >> > > > > > -- > Kees Bakker > Founder > SODAQ > M. 0031617737165 > www.sodaq.com > > _______________________________________________ > devel mailing list > devel@riot-os.org > https://lists.riot-os.org/mailman/listinfo/devel > _______________________________________________ devel mailing list devel@riot-os.org https://lists.riot-os.org/mailman/listinfo/devel
