Document WS2812B level shifter erratum

README.MD

@@ -12,3 +12,7 @@ Board to run [colorchord2](https://github.com/cnlohr/colorchord) on a string of
 	* Workaround: Flip 180 degrees and solder shifted onto the right pads, then use magnet wire to connect the remaining two pads.
 * Serial boot loader non-functional (uses incompatible UART I/Os).
 	* Workaround: Program via JTAG / SWD.
+* Missing level shifters for WS2812B LEDs (RX)
+	* Workaround: Don't use WS2812B RX inputs on the board
+* Missing level shifters for WS2812B LEDs (TX)
+	* Workaround: The first LED will kinda sorta do the level shifting for you, but sometimes fail to display correctly. Just ignore its erratic blinking.

firmware/lib/systems.c

@@ -166,45 +166,6 @@ void ConfigureUART()
 	NVIC_Init(&NVIC_InitStruct);*/
 }
 
-void ConfigureDMX()
-{
-	GPIO_InitTypeDef GPIO_InitStruct;
-	USART_InitTypeDef USART_InitStruct;
-
-	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
-
-	// Set up UART GPIOs
-	GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2);
-	GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2);
-
-	GPIO_InitStruct.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
-	GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
-	GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
-	GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
-	GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
-	GPIO_Init(GPIOB, &GPIO_InitStruct);
-
-	// Set up control GPIOs	
-	GPIO_StructInit(&GPIO_InitStruct);
-	GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
-	GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
-	GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
-	GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
-	GPIO_Init(GPIOB, &GPIO_InitStruct);
-
-	// Set up UART
-	RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
-
-	USART_InitStruct.USART_BaudRate = 250000;
-	USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
-	USART_InitStruct.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
-	USART_InitStruct.USART_Parity = USART_Parity_No;
-	USART_InitStruct.USART_StopBits = USART_StopBits_2;
-	USART_InitStruct.USART_WordLength = USART_WordLength_8b;
-	USART_Init(USART2, &USART_InitStruct);
-	USART_Cmd(USART2, ENABLE);
-}
-
 void ConfigureLED()
 {
 	ConfigureGPIO(LED_RED, INOUT_OUT);

firmware/lib/systems.h

@@ -57,13 +57,7 @@ void ConfigureGPIO( gpio gpio, int parameters );
 #define LED_BLUE (LEDPIN+1)
 #define LED_RED (LEDPIN+2)
 
-#define DMX_TX_EN GPIOOn(1)
-#define DMX_TX_DIS GPIOOff(1)
-#define DMX_RX_EN GPIOOff(0)
-#define DMX_RX_DIS GPIOOn(0)
-
 void ConfigureUART();
-void ConfigureDMX();
 void ConfigureLED();
 
 void JumpToBootloader(void);

firmware/main.c

@@ -111,24 +111,6 @@ void EXTI0_IRQHandler(void)
     }
 }
 
-void test()
-{
-	int i;
-	char str[] = "AAAATest\r\n";
-	char *buf;
-	
-	DMX_TX_EN;
-
-	while (1) {
-		buf = str;	
-		for (i=strlen(buf); i > 0; --i) {
-			while (!(USART2->SR & USART_SR_TXE));
-			USART2->DR = (uint16_t)(*((char*) buf) & 0x01FF);
-			buf++;
-		}
-	}
-}
-
 int main(void)
 {  
 	uint32_t i = 0;
@@ -143,7 +125,6 @@ int main(void)
 	float fv = RCC_Clocks.HCLK_Frequency / 1000000.0f;
 
 	ConfigureUART();
-	ConfigureDMX();
 	InitColorChord();
 	Configure_PA0();
 	InitSPI2812();
@@ -157,7 +138,6 @@ int main(void)
 	
 	int c = 1;
 	LED_ON(LED_RED);
-	test();
 	while (1) {
 		for (int a=0; a < NUM_LIN_LEDS; a++) {
 			ledOut[a*3 + 0] = c/2;