Add UART driver for SAMG

[mcbridejc]

No description provided.

[salkinium]

Very nice, thanks!

[salkinium]

Hm?

 x   samg55g19a-uu          37.4s
In file included from modm/src/modm/platform.hpp:47,
                 from main.cpp:12:
modm/src/modm/platform/uart/uart_7.hpp: In static member function 'static void modm::platform::Uart7::initialize(modm::platform::UartBase::Parity, modm::platform::UartBase::WordLength, uint8_t)':
modm/src/modm/platform/uart/uart_7.hpp:69:3: error: 'USART7' was not declared in this scope; did you mean 'USART2'?
   69 |   USART7->US_BRGR = result.index;
      |   ^~~~~~
      |   USART2

[mcbridejc]

Hm?

 x   samg55g19a-uu          37.4s
In file included from modm/src/modm/platform.hpp:47,
                 from main.cpp:12:
modm/src/modm/platform/uart/uart_7.hpp: In static member function 'static void modm::platform::Uart7::initialize(modm::platform::UartBase::Parity, modm::platform::UartBase::WordLength, uint8_t)':
modm/src/modm/platform/uart/uart_7.hpp:69:3: error: 'USART7' was not declared in this scope; did you mean 'USART2'?
   69 |   USART7->US_BRGR = result.index;
      |   ^~~~~~
      |   USART2

Well, it seems USART7 is only available on the 'j' parts, not the 'g' parts. I guess I need to add some filtering based on the device-pin field in module.lb.

[mcbridejc]

Your tests are good :)

[salkinium]

Well, it seems USART7 is only available on the 'j' parts, not the 'g' parts. I guess I need to add some filtering based on the device-pin field in module.lb.

That's weird, since modm-devices should apply this filter automatically? This smells like a bug in modm-devices, I'll check that out.

[mcbridejc]

That's weird, since modm-devices should apply this filter automatically? This smells like a bug in modm-devices, I'll check that out.

I think I get it. The flexcom driver doesn't have the device-pin field, and I'm using device.has_driver("flexcom:samg*") to find the USARTs. For some reason, the samg55g19 CMSIS header includes FLEXCOM7, but not USART7/SPI7/TWI7. I'm guessing this is a mistake.

[mcbridejc]

I changed to device.has_driver("usart:samg*"), and I think that will fix it.

[salkinium]

Ah, I see. This isn't a bug in modm-devices, but perhaps a bug in the data?
FLEXCOM always has instance 7, but TWI, SPI and USART only have it on J devices?
Can this be correct?

    <driver name="flexcom" type="samg55">
      <instance value="0"/>
      <instance value="1"/>
      <instance value="2"/>
      <instance value="3"/>
      <instance value="4"/>
      <instance value="5"/>
      <instance value="6"/>
      <instance value="7"/>
    </driver>

[mcbridejc]

Ah, I see. This isn't a bug in modm-devices, but perhaps a bug in the data? FLEXCOM always has instance 7, but TWI, SPI and USART only have it on J devices? Can this be correct?

No I don't think so. I don't think it makes sense. I suspect it's just a mistake in the vendor data.