fruchti/laurelin
1
0
Fork 0
Code Issues Pull requests Packages Projects Releases Wiki Activity

Add basic 9-channel BCM output

Browse source
This commit is contained in:
fruchti 2019-12-21 23:41:19 +01:00
parent 66381c3cb6
commit fe7a2f1869
6 changed files with 196 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
build-number.txt
View file

@ -1 +1 @@
0
80

170
src/led.c Normal file
View file

@ -0,0 +1,170 @@
#include "led.h"
#include "stm32f030x6.h"
#define LED_ODR_MASK ((1 << PIN_LED_R_0) | (1 << PIN_LED_G_0) \
| (1 << PIN_LED_B_0) | (1 << PIN_LED_R_1) \
| (1 << PIN_LED_G_1) | (1 << PIN_LED_B_1) \
| (1 << PIN_LED_R_2) | (1 << PIN_LED_G_2) \
| (1 << PIN_LED_B_2))
#define LED_MODER_MASK ((3 << PIN_LED_R_0 * 2) | (3 << PIN_LED_G_0 * 2) \
| (3 << PIN_LED_B_0 * 2) | (3 << PIN_LED_R_1 * 2) \
| (3 << PIN_LED_G_1 * 2) | (3 << PIN_LED_B_1 * 2) \
| (3 << PIN_LED_R_2 * 2) | (3 << PIN_LED_G_2 * 2) \
| (3 << PIN_LED_B_2 * 2))
#define LED_MODER ((1 << PIN_LED_R_0 * 2) | (1 << PIN_LED_G_0 * 2) \
| (1 << PIN_LED_B_0 * 2) | (1 << PIN_LED_R_1 * 2) \
| (1 << PIN_LED_G_1 * 2) | (1 << PIN_LED_B_1 * 2) \
| (1 << PIN_LED_R_2 * 2) | (1 << PIN_LED_G_2 * 2) \
| (1 << PIN_LED_B_2 * 2))
uint8_t LED_Data[LED_COUNT] = {0, 63, 200, 255};
// TIM3 is clocked by APB1 and thus receives only half the system clock. The 4
// LSBs have bit lengths 2, 4, 8, and 16 cycles and are generated blocking from
// an inline assembly block and are thus not in this table.
static const uint16_t LED_BitLengths[LED_BITS - 4] =
{
16, 32, 64, 128, 256, 512, 1024, 2048
};
static uint16_t LED_DMABuffer[LED_BITS + 1];
static void LED_RefreshDMABuffer(void)
{
for(int i = 0; i < LED_COUNT; i++)
{
uint16_t gamma_corrected = (uint16_t)LED_Data[i] * LED_Data[i];
gamma_corrected >>= 16 - LED_BITS;
for(int j = 0; j < LED_BITS; j++)
{
if(gamma_corrected & (1 << j))
{
LED_DMABuffer[j] |= 1 << i;
}
else
{
LED_DMABuffer[j] &= ~(1 << i);
}
}
}
// Data to reset outputs after all data bits are sent
LED_DMABuffer[LED_BITS] = 0x0000;
}
static void LED_StartBCM(void)
{
// Reset DMA and timer
TIM3->CR1 = 0x0000;
TIM3->DIER = 0x0000;
TIM3->CNT = 0;
DMA1_Channel3->CCR = 0x0000;
DMA1_Channel4->CCR = 0x0000;
TIM3->ARR = 1; // Delay before everything starts with the first DMA request
TIM3->CR1 = TIM_CR1_ARPE;
// Since ARPE is set, this write goes to ARR's shadow register
TIM3->ARR = LED_BitLengths[0];
TIM3->DIER = TIM_DIER_UDE | TIM_DIER_CC1DE;
// DMA channel 3: Output data to port a on TIM3 update
DMA1_Channel3->CMAR = (uint32_t)&(LED_DMABuffer[4]);
// One transfer for each bit plus one to set the outputs to zero again.
// The first 4 are sent out with assembly before the first DMA transfer.
DMA1_Channel3->CNDTR = LED_BITS + 1 - 4;
// Highest priority, 16 bits, increment memory, memory to peripheral
DMA1_Channel3->CCR = DMA_CCR_PL | DMA_CCR_MSIZE_0 | DMA_CCR_PSIZE_0
| DMA_CCR_MINC | DMA_CCR_DIR | DMA_CCR_EN | DMA_CCR_TCIE;
// DMA channel 3: Output data to port a on TIM3 update
// The bit lengths table is offset because the first value is already in
// the timer's ARR shadow register.
DMA1_Channel4->CMAR = (uint32_t)&(LED_BitLengths[1]);
// The first four bits are sent out with the assembly code below, so only
// LED_BITS - 5 bit lengths are needed.
DMA1_Channel4->CNDTR = LED_BITS - 1 - 4;
// 16 bits, memory increment mode, memory to peripheral
DMA1_Channel4->CCR = DMA_CCR_MSIZE_0 | DMA_CCR_PSIZE_0 | DMA_CCR_MINC
| DMA_CCR_DIR | DMA_CCR_EN;
// Send the 4 LSBs, set to zero at the end (so the timing is independent
// from the delay intrudoced by the DMA)
__asm__ volatile(".syntax unified\n"
"str %[d0], [%[odr]];"
"str %[d1], [%[odr]];"
"nop;"
"nop;"
"str %[d2], [%[odr]];"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"str %[d3], [%[odr]];"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"nop;"
"str %[zero], [%[odr]];"
:
: [odr] "l" ((uint32_t)&(GPIOA->ODR)),
[d0] "r" (LED_DMABuffer[0]),
[d1] "r" (LED_DMABuffer[1]),
[d2] "r" (LED_DMABuffer[2]),
[d3] "r" (LED_DMABuffer[3]),
[zero] "r" (0)
:);
// Enable TIM3 for the rest of the bits
TIM3->CR1 = TIM_CR1_ARPE | TIM_CR1_CEN;
}
void LED_Init(void)
{
RCC->AHBENR |= RCC_AHBENR_GPIOAEN;
RCC->AHBENR |= RCC_AHBENR_DMA1EN;
RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;
GPIOA->ODR &= ~LED_ODR_MASK;
GPIOA->MODER = (GPIOA->MODER & ~LED_MODER_MASK) | LED_MODER;
TIM3->CR1 = 0x0000;
TIM3->PSC = 0;
// CH1 will be used for DMA requests updating ARR
TIM3->CCMR1 = TIM_CCMR1_OC1M_2 | TIM_CCMR1_OC1M_1;
TIM3->CCER = TIM_CCER_CC1E;
TIM3->CCR1 = 1;
// DMA channel 3: Output data to port a on TIM3 update
DMA1_Channel3->CPAR = (uint32_t)&(GPIOA->ODR);
// DMA channel 4: Update TIM3 ARR on TIM3 CH1 (which is set to 0)
DMA1_Channel4->CPAR = (uint32_t)&(TIM3->ARR);
NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
LED_RefreshDMABuffer();
LED_StartBCM();
}
void DMA1_Channel2_3_IRQHandler(void)
{
// Interrupt when all bits have been sent
DMA1->IFCR = DMA_IFCR_CTCIF3;
// Start sending bits out again
LED_StartBCM();
}

10
src/led.h Normal file
View file

@ -0,0 +1,10 @@
#pragma once
#include "stm32f030x6.h"
#include "pinning.h"
#define LED_BITS 12
#define LED_COUNT 9
void LED_Init(void);

2
src/main.c
View file

@ -2,6 +2,8 @@
int main(void)
{
LED_Init();
while(1)
{
}

1
src/main.h
View file

@ -2,6 +2,7 @@
#include "stm32f030x6.h"
#include "buildid.h"
#include "led.h"
int main(void);

12
src/pinning.h Normal file
View file

@ -0,0 +1,12 @@
#pragma once
// Port A
#define PIN_LED_R_0 0
#define PIN_LED_G_0 1
#define PIN_LED_B_0 2
#define PIN_LED_R_1 3
#define PIN_LED_G_1 4
#define PIN_LED_B_1 5
#define PIN_LED_R_2 6
#define PIN_LED_G_2 7
#define PIN_LED_B_2 9