T4.1 + WS2812B Can I use Serial 8?

[theDVSguy]

Hello, Trying to hook up a simple 8 led strip to a T4.1.
I noticed the WS2812B lib only goes up to T4.0 thus eliminating Serial 8.

Does anyone know a way around this ? I only have one serial left to utilize.
or maybe I should use another library?

thanks

[KurtE]

Looks like it has not been updated for T4.1

I will do a quick and dirty and update, that you can try and then issue PR.

Should not be very difficult.

[KurtE]

I have a fork/branch that you might try out: https://github.com/KurtE/WS2812Serial/tree/teensy41

The main change was to change the code that looked at the pin numbers in the begin method:

#elif defined(__IMXRT1062__)
	  case 1: // Serial1
#if defined(ARDUINO_TEENSY41)
	  case 53:
#endif
		uart = &IMXRT_LPUART6; 
		CCM_CCGR3 |= CCM_CCGR3_LPUART6(CCM_CCGR_ON);
		hwtrigger = DMAMUX_SOURCE_LPUART6_TX; 
		break;
	  case 8: // Serial2
		uart = &IMXRT_LPUART4; 
		CCM_CCGR1 |= CCM_CCGR1_LPUART4(CCM_CCGR_ON);
		hwtrigger = DMAMUX_SOURCE_LPUART4_TX; 
		break;
	  case 14: // Serial3
		uart = &IMXRT_LPUART2; 
		CCM_CCGR0 |= CCM_CCGR0_LPUART2(CCM_CCGR_ON);
		hwtrigger = DMAMUX_SOURCE_LPUART2_TX; 
		break;
	  case 17: // Serial4
		uart = &IMXRT_LPUART3; 
		CCM_CCGR0 |= CCM_CCGR0_LPUART3(CCM_CCGR_ON);
		hwtrigger = DMAMUX_SOURCE_LPUART3_TX; 
		break;
	  case 20: // Serial5
#if defined(ARDUINO_TEENSY40)
	  case 39: // Serial5 alt
#elif defined(ARDUINO_TEENSY41)
	  case 47:
#endif
		uart = &IMXRT_LPUART8; 
		CCM_CCGR6 |= CCM_CCGR6_LPUART8(CCM_CCGR_ON);
		hwtrigger = DMAMUX_SOURCE_LPUART8_TX; 
		break;
	  case 24: // Serial6
		uart = &IMXRT_LPUART1; 
		CCM_CCGR5 |= CCM_CCGR5_LPUART1(CCM_CCGR_ON);
		hwtrigger = DMAMUX_SOURCE_LPUART1_TX; 
		break;
	  case 29: // Serial7
		uart = &IMXRT_LPUART7; 
		CCM_CCGR5 |= CCM_CCGR5_LPUART7(CCM_CCGR_ON);
		hwtrigger = DMAMUX_SOURCE_LPUART7_TX; 
		break;
#if defined(ARDUINO_TEENSY41)
	  case 35:
		uart = &IMXRT_LPUART5; 
		CCM_CCGR3 |= CCM_CCGR3_LPUART5(CCM_CCGR_ON);
		hwtrigger = DMAMUX_SOURCE_LPUART5_TX; 
		break;
#endif		
#endif

Basically the changes are the lines in the sections that have ARDUINO_TEENSY41 or ARDUINO_TEENSY40

If you get a chance you might try a Pull Request.

Note: I updated the examples to show T4.1 as well.

You might give it a shot and see if it works. Will probably go ahead and issue Pull Request hoping it works.

[theDVSguy]

Thanks Appreciate the assistance. I will give it a go

[PaulStoffregen]

Turns out pin 35 is the one exception to the pin mux always using ALT2. I've committed a fix on github:

https://github.com/PaulStoffregen/WS...4bbbe010571848

Confirmed working with real hardware.

[KurtE]

Thanks Paul,

I should have checked it, I did have the HardwareSerial8.cpp up to verify the other stuff like which CCGRx register and which bits... :

static HardwareSerial::hardware_t UART5_Hardware = {
	7, IRQ_LPUART5, &IRQHandler_Serial8, 
	&serialEvent8, &_serialEvent8_default,
	CCM_CCGR3, CCM_CCGR3_LPUART5(CCM_CCGR_ON),
    {{34,1, &IOMUXC_LPUART5_RX_SELECT_INPUT, 1}, {48, 2, &IOMUXC_LPUART5_RX_SELECT_INPUT, 0}},
    {{35,1, &IOMUXC_LPUART5_TX_SELECT_INPUT, 1}, {0xff, 0xff, nullptr, 0}},

I did wonder if you set the TX pin to half duplex or not... Did not think so, sod did not have to worry about IOMUXC_LPUART5_TX_SELECT_INPUT

Glad it is working