From 3fa39721d79a7548c34ed2a486e81636287bb0e1 Mon Sep 17 00:00:00 2001
From: cnlohr <lohr85@gmail.com>
Date: Mon, 27 Feb 2023 06:06:31 -0500
Subject: [PATCH] Update ws2812b demo to be more robust.
---
ch32v003evt/startup_ch32v003.c | 41 ++++++-----
examples/ws2812demo/README.md | 36 ++++++++--
.../ws2812demo/ws2812b_dma_spi_led_driver.h | 72 ++++++++++---------
examples/ws2812demo/ws2812bdemo.c | 68 +++++++++---------
4 files changed, 128 insertions(+), 89 deletions(-)
diff --git a/ch32v003evt/startup_ch32v003.c b/ch32v003evt/startup_ch32v003.c
index af0f40c..8e486b8 100644
--- a/ch32v003evt/startup_ch32v003.c
+++ b/ch32v003evt/startup_ch32v003.c
@@ -9,7 +9,7 @@
int main() __attribute__((used));
void SystemInit( void ) __attribute__((used));
-void _start() __attribute__((naked)) __attribute((section(".init"))) __attribute__((used));
+void InterruptVector() __attribute__((naked)) __attribute((section(".init"))) __attribute__((used));
void handle_reset() __attribute__((naked)) __attribute((section(".text.handle_reset"))) __attribute__((used));
void DefaultIRQHandler( void ) __attribute__((section(".text.vector_handler"))) __attribute__((naked)) __attribute__((used));
@@ -55,7 +55,7 @@ void TIM1_TRG_COM_IRQHandler( void ) __attribute__((section(".text.vector_ha
void TIM1_CC_IRQHandler( void ) __attribute__((section(".text.vector_handler"))) __attribute((weak,alias("DefaultIRQHandler"))) __attribute__((used));
void TIM2_IRQHandler( void ) __attribute__((section(".text.vector_handler"))) __attribute((weak,alias("DefaultIRQHandler"))) __attribute__((used));
-void _start()
+void InterruptVector()
{
asm volatile( "\n\
.align 2\n\
@@ -111,29 +111,38 @@ void handle_reset()
.option norelax\n\
la gp, __global_pointer$\n\
.option pop\n\
- la sp, _eusrstack\n" );
+ la sp, _eusrstack\n"
- // Load data section from flash to RAM
- uint32_t * tempin = _data_lma;
- uint32_t * tempout = _data_vma;
- while( tempout != _edata )
- *(tempout++) = *(tempin++);
-
- tempout = _sbss;
- while( tempout < _ebss )
- *(tempout++) = 0;
+ // Setup the interrupt vector.
-asm volatile( "\n\
- li t0, 0x80\n\
+" li t0, 0x80\n\
csrw mstatus, t0\n\
li t0, 0x3\n\
csrw 0x804, t0\n\
- la t0, _start\n\
+ la t0, InterruptVector\n\
ori t0, t0, 3\n\
- csrw mtvec, t0" );
+ csrw mtvec, t0\n"
+
+ // Clear BSS
+ // Has to be in assembly otherwise it will overwrite the stack.
+ "la t0, _sbss\n\
+ la t1, _ebss\n\
+ bgeu t0, t1, 2f\n\
+1:\n\
+ sw zero, (t0)\n\
+ addi t0, t0, 4\n\
+ bltu t0, t1, 1b\n\
+2:" );
+
+ // Load data section from flash to RAM
+ uint32_t * tempin = _data_lma;
+ uint32_t * tempout = _data_vma;
+ while( tempout != _edata )
+ *(tempout++) = *(tempin++);
SystemInit();
+ // set mepc to be main as the root interrupt.
asm volatile( "\n\
la t0, main\n\
csrw mepc, t0\n\
diff --git a/examples/ws2812demo/README.md b/examples/ws2812demo/README.md
index 6894ecd..a2dcdbb 100644
--- a/examples/ws2812demo/README.md
+++ b/examples/ws2812demo/README.md
@@ -1,6 +1,6 @@
# WS2812B SPI DMA example
-This example uses SPI-DMA to output WS2812B LEDs. By chunking the outputs using the center-interrupt, it is possible to double-buffer the WS2812B output data while only storing a few LEDs worth of data in memory at once.
+Single-file-header for SPI-DMA to output WS2812B LEDs. By chunking the outputs using the center-interrupt, it is possible to double-buffer the WS2812B output data while only storing a few LEDs worth of data in memory at once.
This outputs the LED data on the MOSI (PC6) pin of the CH32V003.
@@ -8,10 +8,34 @@ Additionally, this demo only uses 6% CPU while it's outputting LEDs and free whi
The timing on the SPI bus is not terribly variable, the best I was able to find was:
-Ton0 = 324ns
-Ton1 = 990ns
-Toff0 = 990ns
-Toff1 = 324ns
-Treset = 68us
+* Ton0 = 324ns
+* Ton1 = 990ns
+* Toff0 = 990ns
+* Toff1 = 324ns
+* Treset = 68us
+## Usage
+
+If you are including this in main, simply
+```c
+#define WS2812DMA_IMPLEMENTATION
+#include "ws2812b_dma_spi_led_driver.h"
+```
+
+You will need to implement the following two functions, as callbacks from the ISR.
+```c
+uint32_t CallbackWS2812BLED( int ledno );
+```
+
+You willalso need to call
+```c
+InitWS2812DMA();
+```
+
+Then, whenyou want to update the LEDs, call:
+```c
+WS2812BStart( int num_leds );
+```
+
+If you want to see if it's done sending, examine `WS2812BLEDInUse`.
diff --git a/examples/ws2812demo/ws2812b_dma_spi_led_driver.h b/examples/ws2812demo/ws2812b_dma_spi_led_driver.h
index f0f143c..fd1d428 100644
--- a/examples/ws2812demo/ws2812b_dma_spi_led_driver.h
+++ b/examples/ws2812demo/ws2812b_dma_spi_led_driver.h
@@ -29,9 +29,6 @@ void WS2812BDMAStart( int leds );
// Callbacks that you must implement.
uint32_t WS2812BLEDCallback( int ledno );
-extern volatile int WS2812BLEDDone;
-
-
#ifdef WS2812DMA_IMPLEMENTATION
// Note first 2 LEDs of DMA Buffer are 0's as a "break"
@@ -40,17 +37,16 @@ extern volatile int WS2812BLEDDone;
// 1: Divisble by 2.
// 2:
#define DMALEDS 16
-#define WS2812B_RESET_PERIOD 6
+#define WS2812B_RESET_PERIOD 2
#define DMA_BUFFER_LEN (((DMALEDS+1)/2)*6)
static uint16_t WS2812dmabuff[DMA_BUFFER_LEN];
-static int WS2812LEDs;
-static int WS2812LEDPlace;
-volatile int WS2812BLEDDone;
-
+static volatile int WS2812LEDs;
+static volatile int WS2812LEDPlace;
+static volatile int WS2812BLEDInUse;
// This is the code that updates a portion of the WS2812dmabuff with new data.
// This effectively creates the bitstream that outputs to the LEDs.
-static void WS2812FillBuffSec( uint16_t * ptr, int numhalfwords, int ending )
+static void WS2812FillBuffSec( uint16_t * ptr, int numhalfwords, int tce )
{
const static uint16_t bitquartets[16] = {
0b1000100010001000, 0b1000100010001110, 0b1000100011101000, 0b1000100011101110,
@@ -65,6 +61,10 @@ static void WS2812FillBuffSec( uint16_t * ptr, int numhalfwords, int ending )
while( place < 0 && ptr != end )
{
+ (*ptr++) = 0;
+ (*ptr++) = 0;
+ (*ptr++) = 0;
+ (*ptr++) = 0;
(*ptr++) = 0;
(*ptr++) = 0;
place++;
@@ -78,22 +78,18 @@ static void WS2812FillBuffSec( uint16_t * ptr, int numhalfwords, int ending )
while( ptr != end )
(*ptr++) = 0;//0xffff;
- // If we're "totally finished" we can set the flag.
- if( place == ledcount+1 )
- WS2812BLEDDone = 1;
-
// Only safe to do this when we're on the second leg.
- if( ending )
+ if( tce )
{
if( place == ledcount )
{
// Take the DMA out of circular mode and let it expire.
DMA1_Channel3->CFGR &= ~DMA_Mode_Circular;
+ WS2812BLEDInUse = 0;
}
place++;
}
-
break;
}
@@ -113,42 +109,48 @@ static void WS2812FillBuffSec( uint16_t * ptr, int numhalfwords, int ending )
void DMA1_Channel3_IRQHandler( void ) __attribute__((interrupt));
void DMA1_Channel3_IRQHandler( void )
{
- //GPIOD->BSHR = 1; // Turn on GPIOD0
+ //GPIOD->BSHR = 1; // Turn on GPIOD0 for profiling
// Backup flags.
- int intfr = DMA1->INTFR;
-
- // Clear all possible flags.
- DMA1->INTFCR = DMA1_IT_GL3;
-
- if( intfr & DMA1_IT_HT3 )
+ volatile int intfr = DMA1->INTFR;
+ do
{
- // Complete (Fill in second part)
- WS2812FillBuffSec( WS2812dmabuff + DMA_BUFFER_LEN / 2, DMA_BUFFER_LEN / 2, 1 );
- }
- if( intfr & DMA1_IT_TC3 )
- {
- // Halfwaay (Fill in first part)
- WS2812FillBuffSec( WS2812dmabuff, DMA_BUFFER_LEN / 2, 0 );
- }
+ // Clear all possible flags.
+ DMA1->INTFCR = DMA1_IT_GL3;
- //GPIOD->BSHR = 1<<16; // Turn off GPIOD0
+ if( intfr & DMA1_IT_HT3 )
+ {
+ // Halfwaay (Fill in first part)
+ WS2812FillBuffSec( WS2812dmabuff, DMA_BUFFER_LEN / 2, 1 );
+ }
+ if( intfr & DMA1_IT_TC3 )
+ {
+ // Complete (Fill in second part)
+ WS2812FillBuffSec( WS2812dmabuff + DMA_BUFFER_LEN / 2, DMA_BUFFER_LEN / 2, 0 );
+ }
+ intfr = DMA1->INTFR;
+ } while( intfr );
+
+ //GPIOD->BSHR = 1<<16; // Turn off GPIOD0 for profiling
}
void WS2812BDMAStart( int leds )
{
- WS2812BLEDDone = 0;
+ __disable_irq();
+ WS2812BLEDInUse = 1;
+ DMA1_Channel3->CFGR &= ~DMA_Mode_Circular;
+ DMA1_Channel3->CNTR = 0;
+ DMA1_Channel3->MADDR = (uint32_t)WS2812dmabuff;
WS2812LEDs = leds;
WS2812LEDPlace = -WS2812B_RESET_PERIOD;
WS2812FillBuffSec( WS2812dmabuff, DMA_BUFFER_LEN, 0 );
- DMA1_Channel3->CFGR |= DMA_Mode_Circular;
DMA1_Channel3->CNTR = DMA_BUFFER_LEN; // Number of unique uint16_t entries.
+ DMA1_Channel3->CFGR |= DMA_Mode_Circular;
+ __enable_irq();
}
void WS2812BDMAInit( )
{
- WS2812BLEDDone = 1;
-
// Enable DMA + Peripherals
RCC->AHBPCENR |= RCC_AHBPeriph_DMA1;
RCC->APB2PCENR |= RCC_APB2Periph_GPIOC | RCC_APB2Periph_SPI1;
diff --git a/examples/ws2812demo/ws2812bdemo.c b/examples/ws2812demo/ws2812bdemo.c
index a74a420..32ce933 100644
--- a/examples/ws2812demo/ws2812bdemo.c
+++ b/examples/ws2812demo/ws2812bdemo.c
@@ -65,22 +65,22 @@ void SystemInit(void)
USART1->CTLR1 |= CTLR1_UE_Set;
}
-#define NR_LEDS 197
+#define NR_LEDS 191
uint16_t phases[NR_LEDS];
int frameno;
-int tween = 0;
-int tweendir = 0;
+volatile int tween = 0;
// Callbacks that you must implement.
uint32_t WS2812BLEDCallback( int ledno )
{
uint8_t index = (phases[ledno])>>8;
uint8_t rs = sintable[index]>>3;
-// uint32_t fire = huetable[(rs+190&0xff)] | (huetable[(rs+30&0xff)]<<8) | (huetable[(rs+0)]<<16);
+ uint32_t fire = huetable[(rs+190&0xff)] | (huetable[(rs+30&0xff)]<<8) | (huetable[(rs+0)]<<16);
uint32_t ice = 0xff | ((rs)<<8) | (rs<<16);
- return ice;
- //return TweenHexColors( fire, ice, tween ); // Where "tween" is a value from 0 ... 255
+
+ // Because this chip doesn't natively support multiplies, this can be very slow.
+ return TweenHexColors( fire, ice, tween ); // Where "tween" is a value from 0 ... 255
}
int main()
@@ -101,37 +101,41 @@ int main()
for( k = 0; k < NR_LEDS; k++ ) phases[k] = k<<8;
+ int tweendir = 0;
+
while(1)
{
// Wait for LEDs to totally finish.
- if( WS2812BLEDDone )
+ Delay_Ms( 12 );
+
+ while( WS2812BLEDInUse );
+
+ frameno++;
+
+ if( frameno == 1024 )
+ {
+ tweendir = 4;
+ }
+ if( frameno == 2048 )
{
- frameno++;
-
- if( frameno == 1024 )
- {
- tweendir = 4;
- }
- if( frameno == 2048 )
- {
- tweendir = -4;
- frameno = 0;
- }
-
- if( tweendir )
- {
- tween += tweendir;
- if( tween > 255 ) tween = 255;
- if( tween < 0 ) tween = 0;
- }
-
- for( k = 0; k < NR_LEDS; k++ )
- {
- phases[k] += ((((rands[k&0xff])+0xf)<<2) + (((rands[k&0xff])+0xf)<<1))>>1;
- }
-
- WS2812BDMAStart( NR_LEDS );
+ tweendir = -4;
+ frameno = 0;
}
+
+ if( tweendir )
+ {
+ int t = tween + tweendir;
+ if( t > 255 ) t = 255;
+ if( t < 0 ) t = 0;
+ tween = t;
+ }
+
+ for( k = 0; k < NR_LEDS; k++ )
+ {
+ phases[k] += ((((rands[k&0xff])+0xf)<<2) + (((rands[k&0xff])+0xf)<<1))>>1;
+ }
+
+ WS2812BDMAStart( NR_LEDS );
}
}
--
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