Document WS2812B level shifter erratum

README.MD

@@ -1 +1,18 @@
-# Sabik WS2812B light signal - CPU Board
+# WS2812B light signal - CPU Board
+
+Board to run [colorchord2](https://github.com/cnlohr/colorchord) on a string of WS2812B LEDs with live line-in audio.
+
+## Errata (Rev 01)
+
+* Opamp inverting / non-inverting inputs are swapped
+	* Workaround: Lift pads 2 and 3, and 5 and 6, and connect them crossed using magnet wire.
+* Opamp is not rail-to-rail and does not allow to use the ADC in full range
+	* Workaround: Only use limited range -640 to 520.
+* LED footprint is wrong.
+	* 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/Makefile

@@ -13,9 +13,8 @@ OD=$(PREFIX)-objdump
 OBJCOPYFLAGS = -O binary
 
 BIN=$(CP) -O ihex 
-
 CCBASE = colorchord/embeddedstm32f407
-DEFS =  -DSTM32F40_41xxx  -DHSE_VALUE=8000000
+DEFS =  -DSTM32F40_41xxx  -DHSE_VALUE=8000000 -DREVISION=\"`git describe --match=NeVeRmAtCh --always --abbrev=40 --dirty`\"
 STARTUP = $(CCBASE)/lib/startup_stm32f40_41xxx.s
 STLIB = $(CCBASE)/STM32F4xx_StdPeriph_Driver
 EMCOM = $(CCBASE)/../embeddedcommon

firmware/adc.c

@@ -14,8 +14,6 @@ void adc_init()
 	ADC_InitTypeDef ADC_InitStructure;
 	GPIO_InitTypeDef GPIO_InitStruct;
 
-	printf("ADC init\r\n");
-
 	// Enable Clocks
 	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
 	RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
@@ -30,7 +28,7 @@ void adc_init()
 	// Set up timer
 	TIM_TimeBaseInitTypeDef Timer_InitStruct;
 	TIM_TimeBaseStructInit(&Timer_InitStruct);
-	Timer_InitStruct.TIM_Prescaler = 0x0;
+	Timer_InitStruct.TIM_Prescaler = 0;
 	Timer_InitStruct.TIM_CounterMode = TIM_CounterMode_Up;
 	Timer_InitStruct.TIM_Period = (ADC_F_TIM / ADC_SAMPLE_RATE);
 	Timer_InitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
@@ -46,7 +44,7 @@ void adc_init()
 	TIM_OC1Init (TIM5, &TIM_OCInitStructure);
 	
 	TIM_SetCompare1(TIM5, 0xFFFF);
-	TIM_ITConfig(TIM5, TIM_IT_CC1, ENABLE);
+	// Let's leave the interrupt disabled until we are done configuring everything
 	
 	TIM_CCxCmd(TIM5, TIM_Channel_1, TIM_CCx_Enable);
 	TIM_CCxNCmd(TIM5, TIM_Channel_1, TIM_CCx_Enable);
@@ -127,44 +125,38 @@ void adc_init()
 	// Turn it all on
 	ADC_Cmd(ADC1, ENABLE);
 	ADC_DMACmd(ADC1, ENABLE);
+}
 
-	printf("adc init done.\r\n");
+void adc_start()
-	printf("ADC  CR1: %08x,  CR2: %08x\r\n", ADC1->CR1, ADC1->CR2);
+{
-	printf("ADC SQR1: %08x, SQR3: %08x\r\n", ADC1->SQR1, ADC1->SQR3);
+	TIM_ITConfig(TIM5, TIM_IT_CC1, ENABLE);
-	printf("DMA2 S0CR: %08x\r\n", ADC_RX_DMA_STREAM->CR);
-	printf("ADC init complete.\r\n");
 }
 
 void DMA2_Stream0_IRQHandler()
 {
 	int sample;
-	DMA_ClearFlag(ADC_RX_DMA_STREAM, DMA_FLAG_TCIF0);
+	int peaking;
-	//printf("[DMA-IRQ] %d, %d\r\n", adc_buffer[0], adc_buffer[1]);
-	//sample = 2048 - ((adc_buffer[0] + adc_buffer[1]) / 2);
-	sample = 2048 - adc_buffer[0];
-	//printf("ADC0: %4d, ADC1: %4d, SMP: %4d\r\n",
-	//	adc_buffer[0], adc_buffer[1], sample);
 
-	GotSample(sample);
+	DMA_ClearFlag(ADC_RX_DMA_STREAM, DMA_FLAG_TCIF0);
+
+	sample = ((adc_buffer[0] + adc_buffer[1]) / 2) - 2048;
+	peaking = (adc_buffer[0] < -640+2048) || (adc_buffer[0] > 520+2048);
+	peaking |= (adc_buffer[1] < -640+2048) || (adc_buffer[1] > 520+2048);
+
+	GotSample(sample, peaking);
 }
 
-// Not used:
+// Only for debugging. Currently disabled.
 void ADC_IRQHandler()
 {
 	ADC_ClearFlag(ADC1, ADC_FLAG_EOC);
-	//printf("[ADC-IRQ] %d, %d\r\n", adc_buffer[0], adc_buffer[1]);
+	// printf("[ADC-IRQ] %d, %d\r\n", adc_buffer[0], adc_buffer[1]);
 }
 
 void TIM5_IRQHandler()
 {
 	TIM_ClearFlag(TIM5, TIM_FLAG_CC1);
 	// I would really like to this in HW via events, but somehow it's broken...
-		/*static int s=0;
+
-	s=!s;
-	if (s) {
-		LED_ON2;
-	} else {
-		LED_OFF2;
-	}*/
 	ADC_SoftwareStartConv(ADC1);
 }

firmware/adc.h

@@ -11,5 +11,6 @@
 // TODO: Update the IRQ handler in adc.c when updating the stream / channel.
 
 void adc_init();
+void adc_start();
 
 #endif

firmware/ccconfig.h

@@ -2,8 +2,8 @@
 #define _CCCONFIG_H
 
 #define CCEMBEDDED
-#define NUM_LIN_LEDS 48
+#define NUM_LIN_LEDS 60
-#define USE_NUM_LIN_LEDS 48
+#define USE_NUM_LIN_LEDS 60
 #define DFREQ (40000)
 
 #endif

firmware/lib/systems.c

@@ -168,8 +168,9 @@ void ConfigureUART()
 
 void ConfigureLED()
 {
-	ConfigureGPIO(LEDPIN, INOUT_OUT);
+	ConfigureGPIO(LED_RED, INOUT_OUT);
-	ConfigureGPIO(LEDPIN2, INOUT_OUT);
+	ConfigureGPIO(LED_GREEN, INOUT_OUT);
+	ConfigureGPIO(LED_BLUE, INOUT_OUT);
 }
 
 uint8_t GetGPIOFromString( const char * str )
@@ -263,3 +264,29 @@ void ConfigureGPIO( uint8_t gpio, int parameters )
 	GPIO_Init(GPIOOf(gpio), &GPIO_InitStructure);
 }
 
+void JumpToBootloader(void) {
+	// Many thanks to https://stm32f4-discovery.net/2017/04/tutorial-jump-system-memory-software-stm32/
+
+	void (*SysMemBootJump)(void);
+	volatile uint32_t addr = 0x1FFF0000;
+
+	RCC_DeInit();
+
+	// Disable and reset systick
+	SysTick->CTRL = 0;
+	SysTick->LOAD = 0;
+	SysTick->VAL = 0;
+
+	__disable_irq();
+
+	// Remap system memory	
+	SYSCFG->MEMRMP = 0x01;
+
+	SysMemBootJump = (void (*)(void)) (*((uint32_t *)(addr + 4)));
+
+	// Set main stack pointer
+	__set_MSP(*(uint32_t *)addr);
+
+	// Jump
+	SysMemBootJump();
+}

firmware/lib/systems.h

@@ -51,19 +51,19 @@ void ConfigureGPIO( gpio gpio, int parameters );
 #define LEDPIN 0x18
 #elif defined( STM32F40_41xxx )
 #define LEDPIN (16+13)
-#define LEDPIN2 (16+14)
 #endif
 
+#define LED_GREEN (LEDPIN+0)
+#define LED_BLUE (LEDPIN+1)
+#define LED_RED (LEDPIN+2)
+
 void ConfigureUART();
-
 void ConfigureLED();
-#define LED_TOGGLE {GPIOOf(LEDPIN)->ODR^=(1<<((LEDPIN)&0x0f));}
-#define LED_ON     GPIOOn(LEDPIN)
-#define LED_OFF    GPIOOff(LEDPIN)
 
-#define LED_ON2     GPIOOn(LEDPIN2)
+void JumpToBootloader(void);
-#define LED_OFF2    GPIOOff(LEDPIN2)
 
+#define LED_ON(p)     GPIOOn(p)
+#define LED_OFF(p)    GPIOOff(p)
 
 #endif
 

firmware/main.c

@@ -25,17 +25,20 @@ int16_t sampbuff[CIRCBUFSIZE];
 volatile int samples;
 
 //This gets called by the ADC/Microphone
-void GotSample( int samp )
+void GotSample(int samp, int peaking)
 {
 	//printf("[GOT-SMP] %d\r\n", samp);
 	sampbuff[last_samp_pos] = samp;
 	last_samp_pos = ((last_samp_pos+1)%CIRCBUFSIZE);
 	samples++;
 
-	if (samp > 128) {
+	if (peaking) {
-		LED_ON2;
+		LED_ON(LED_RED);
+	} else if (samp > 128) {
+		LED_ON(LED_BLUE);
 	} else {
-		LED_OFF2;
+		LED_OFF(LED_BLUE);
+		// Red LED reset in main loop
 	}
 }
 
@@ -114,9 +117,7 @@ int main(void)
 
 	RCC_GetClocksFreq( &RCC_Clocks );
 
-  	ConfigureLED(); 
+	ConfigureLED();
-
-	LED_OFF;
 
 	// SysTick end of count event each 10ms
 	SysTick_Config( RCC_Clocks.HCLK_Frequency / 100);
@@ -129,15 +130,14 @@ int main(void)
 	InitSPI2812();
 	adc_init();
 
-	printf("Operating at %.3fMHz\r\n", fv );
+	printf("\r\nThis is Sabik-CPU, commit %s.\r\n", REVISION);
+	printf("Operating at %.3fMHz.\r\n", fv );
 
 	int this_samp = 0;
 	int wf = 0;
 	
-	LED_ON;
-	LED_ON2;
-	
 	int c = 1;
+	LED_ON(LED_RED);
 	while (1) {
 		for (int a=0; a < NUM_LIN_LEDS; a++) {
 			ledOut[a*3 + 0] = c/2;
@@ -148,17 +148,31 @@ int main(void)
 		SendSPI2812(ledOut, NUM_LIN_LEDS);
 		_delay_us(10*1000);
 		c++;
-		if (c==64)
+		if (c==16) {
+			LED_OFF(LED_RED);
+			LED_ON(LED_BLUE);
+		} else if (c==32) {
+			LED_OFF(LED_BLUE);
+			LED_ON(LED_GREEN);
+		} else if (c==48) {
+			LED_OFF(LED_GREEN);
+		} else if (c==64) {
 			break;
+		}
 	}
 
-	LED_OFF2;
+	LED_OFF(LED_RED);
+	LED_OFF(LED_GREEN);
+	LED_OFF(LED_BLUE);
+
 	SendSPI2812(ledOut, NUM_LIN_LEDS);
+	adc_start();
+
 	while(1)
 	{
 		if( this_samp != last_samp_pos )
 		{
-			LED_OFF; //Use led on the board to show us how much CPU we're using. (You can also probe PB15)
+			LED_OFF(LED_GREEN); //Use led on the board to show us how much CPU we're using. (You can also probe PB15)
 
 			PushSample32( sampbuff[this_samp] ); //Can't put in full volume. (here was /2)
 
@@ -169,10 +183,11 @@ int main(void)
 			{
 				NewFrame();
 				wf = 0; 
+				LED_OFF(LED_RED);
 			}
-			LED_ON;
+			LED_ON(LED_GREEN);
 		}
-		LED_ON; //Take up a little more time to make sure we don't miss this.
+		LED_ON(LED_GREEN); //Take up a little more time to make sure we don't miss this.
 	}
 }
 

firmware/spi2812.c

@@ -133,8 +133,6 @@ void InitSPI2812()
 	GPIO_InitTypeDef  GPIO_InitStructure;
 	NVIC_InitTypeDef nvic_init_struct;
 
-	printf("Init SPI2812: sizeof(MyBuffer)=%d\r\n", sizeof(MyBuffer));
-
 #ifdef STM32F30X
 
 	//On SPI2, PORT B.15