Add meaningful colour struct, double buffering
This commit is contained in:
parent
bc062dac9b
commit
fff3b133c1
|
@ -1 +1 @@
|
|||
129
|
||||
137
|
||||
|
|
70
src/led.c
70
src/led.c
|
@ -1,6 +1,9 @@
|
|||
#include "led.h"
|
||||
#include "stm32f030x6.h"
|
||||
|
||||
LED_Colour_t LED_PixelData[LED_ROWS * LED_COLUMNS / 3] = {{0}};
|
||||
volatile bool LED_FrameFlag = false;
|
||||
|
||||
#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) \
|
||||
|
@ -22,8 +25,6 @@
|
|||
| (1 << PIN_LED_B_2 * 2) | (1 << PIN_LED_R_3 * 2) \
|
||||
| (1 << PIN_LED_G_3 * 2) | (1 << PIN_LED_B_3 * 2))
|
||||
|
||||
uint8_t LED_Data[LED_ROWS][LED_COLUMNS] = {{0}};
|
||||
|
||||
// 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.
|
||||
|
@ -40,15 +41,35 @@ static const int LED_Pins[LED_COLUMNS] =
|
|||
PIN_LED_R_3, PIN_LED_G_3, PIN_LED_B_3
|
||||
};
|
||||
|
||||
static uint16_t LED_DMABuffer[LED_ROWS * (LED_BITS + 1)];
|
||||
// Number of 16-bit values to be transferred to the GPIO's output register via
|
||||
// DMA. Each value contains output values for all columns. For each row, a
|
||||
// value for each bit is needed, plus a constant last transfer to turn all LEDs
|
||||
// off during the processing time.
|
||||
#define LED_DMA_BUFFER_LENGTH (LED_ROWS * (LED_BITS + 1))
|
||||
|
||||
static void LED_RefreshDMABuffer(void)
|
||||
// Define buffers for double buffering
|
||||
static uint16_t LED_DMABuffer1[LED_DMA_BUFFER_LENGTH];
|
||||
static uint16_t LED_DMABuffer2[LED_DMA_BUFFER_LENGTH];
|
||||
static uint16_t *volatile LED_FrontBuffer = LED_DMABuffer1;
|
||||
static uint16_t *volatile LED_BackBuffer = LED_DMABuffer2;
|
||||
|
||||
// If true, front and back buffers will be swapped after the current frame
|
||||
static volatile bool LED_QueuePageFlip = false;
|
||||
|
||||
void LED_Commit(void)
|
||||
{
|
||||
// Wait for the current data to be displayed in case LED_Commit was called
|
||||
// more than one time during a single frame. Otherwise, a race condition
|
||||
// might occur.
|
||||
while(LED_QueuePageFlip);
|
||||
|
||||
for(int r = 0; r < LED_ROWS; r++)
|
||||
{
|
||||
for(int i = 0; i < LED_COLUMNS; i++)
|
||||
{
|
||||
uint16_t gamma_corrected = (uint16_t)LED_Data[r][i];
|
||||
// Use pixel data as a raw byte buffer to get R, G, B in order
|
||||
uint8_t colour_value = ((uint8_t*)LED_PixelData)[r * LED_COLUMNS + i];
|
||||
uint16_t gamma_corrected = (uint16_t)colour_value;
|
||||
gamma_corrected *= gamma_corrected;
|
||||
gamma_corrected >>= 16 - LED_BITS;
|
||||
|
||||
|
@ -56,18 +77,20 @@ static void LED_RefreshDMABuffer(void)
|
|||
{
|
||||
if(gamma_corrected & (1 << j))
|
||||
{
|
||||
LED_DMABuffer[r * (LED_BITS + 1) + j] &=
|
||||
LED_BackBuffer[r * (LED_BITS + 1) + j] &=
|
||||
~(1 << LED_Pins[i]);
|
||||
}
|
||||
else
|
||||
{
|
||||
LED_DMABuffer[r * (LED_BITS + 1) + j] |= 1 << LED_Pins[i];
|
||||
LED_BackBuffer[r * (LED_BITS + 1) + j] |= 1 << LED_Pins[i];
|
||||
}
|
||||
}
|
||||
}
|
||||
// Data to reset outputs after all data bits are sent
|
||||
LED_DMABuffer[r * (LED_BITS + 1) + LED_BITS] = LED_ODR_MASK;
|
||||
LED_BackBuffer[r * (LED_BITS + 1) + LED_BITS] = LED_ODR_MASK;
|
||||
}
|
||||
|
||||
LED_QueuePageFlip = true;
|
||||
}
|
||||
|
||||
static void LED_StartBCM(int row)
|
||||
|
@ -86,7 +109,7 @@ static void LED_StartBCM(int row)
|
|||
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[row * (LED_BITS + 1) + 4]);
|
||||
DMA1_Channel3->CMAR = (uint32_t)&(LED_FrontBuffer[row * (LED_BITS + 1) + 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;
|
||||
|
@ -137,10 +160,10 @@ static void LED_StartBCM(int row)
|
|||
"str %[off], [%[odr]];"
|
||||
:
|
||||
: [odr] "l" ((uint32_t)&(GPIOA->ODR)),
|
||||
[d0] "r" (LED_DMABuffer[row * (LED_BITS + 1) + 0]),
|
||||
[d1] "r" (LED_DMABuffer[row * (LED_BITS + 1) + 1]),
|
||||
[d2] "r" (LED_DMABuffer[row * (LED_BITS + 1) + 2]),
|
||||
[d3] "r" (LED_DMABuffer[row * (LED_BITS + 1) + 3]),
|
||||
[d0] "r" (LED_FrontBuffer[row * (LED_BITS + 1) + 0]),
|
||||
[d1] "r" (LED_FrontBuffer[row * (LED_BITS + 1) + 1]),
|
||||
[d2] "r" (LED_FrontBuffer[row * (LED_BITS + 1) + 2]),
|
||||
[d3] "r" (LED_FrontBuffer[row * (LED_BITS + 1) + 3]),
|
||||
[off] "r" (LED_ODR_MASK)
|
||||
:);
|
||||
|
||||
|
@ -156,6 +179,15 @@ static inline void LED_PulseRowClock(void)
|
|||
GPIOF->BRR = (1 << PIN_ROW_SCK);
|
||||
}
|
||||
|
||||
static inline void LED_PageFlip(void)
|
||||
{
|
||||
uint16_t *volatile tmp;
|
||||
tmp = LED_FrontBuffer;
|
||||
LED_FrontBuffer = LED_BackBuffer;
|
||||
LED_BackBuffer = tmp;
|
||||
LED_QueuePageFlip = false;
|
||||
}
|
||||
|
||||
void LED_Init(void)
|
||||
{
|
||||
RCC->AHBENR |= RCC_AHBENR_GPIOAEN;
|
||||
|
@ -163,6 +195,12 @@ void LED_Init(void)
|
|||
RCC->AHBENR |= RCC_AHBENR_DMA1EN;
|
||||
RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;
|
||||
|
||||
// Fill both DMA buffers
|
||||
LED_Commit();
|
||||
LED_PageFlip();
|
||||
LED_Commit();
|
||||
LED_PageFlip();
|
||||
|
||||
GPIOF->ODR &= ~(1 << PIN_ROW_SCK) & ~(1 << PIN_ROW_DATA);
|
||||
GPIOF->MODER = (GPIOF->MODER
|
||||
& ~(0x3 << PIN_ROW_SCK * 2) & ~(0x3 << PIN_ROW_DATA * 2))
|
||||
|
@ -198,7 +236,6 @@ void LED_Init(void)
|
|||
|
||||
NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
|
||||
|
||||
LED_RefreshDMABuffer();
|
||||
LED_StartBCM(0);
|
||||
}
|
||||
|
||||
|
@ -215,6 +252,11 @@ void DMA1_Channel2_3_IRQHandler(void)
|
|||
current_row = 0;
|
||||
LED_PulseRowClock();
|
||||
GPIOF->BSRR = 1 << PIN_ROW_DATA;
|
||||
if(LED_QueuePageFlip)
|
||||
{
|
||||
LED_PageFlip();
|
||||
}
|
||||
LED_FrameFlag = true;
|
||||
}
|
||||
else
|
||||
{
|
||||
|
|
19
src/led.h
19
src/led.h
|
@ -1,5 +1,7 @@
|
|||
#pragma once
|
||||
|
||||
#include <stdbool.h>
|
||||
|
||||
#include "stm32f030x6.h"
|
||||
#include "pinning.h"
|
||||
|
||||
|
@ -7,5 +9,22 @@
|
|||
#define LED_ROWS 8 // Rows are driven by a shift register
|
||||
#define LED_COLUMNS 12 // Columns are driven by the MCU directly
|
||||
|
||||
typedef struct
|
||||
{
|
||||
uint8_t r;
|
||||
uint8_t g;
|
||||
uint8_t b;
|
||||
} __attribute__((packed)) LED_Colour_t;
|
||||
|
||||
// Pixel data, not displayed until LED_Commit() is called
|
||||
extern LED_Colour_t LED_PixelData[LED_ROWS * LED_COLUMNS / 3];
|
||||
|
||||
// Is set to true for every frame, can be used for timing or synchronisation
|
||||
// externally. Will not be set to false within led.c.
|
||||
extern volatile bool LED_FrameFlag;
|
||||
|
||||
void LED_Init(void);
|
||||
|
||||
// Display LED_PixelData, starting with the next frame
|
||||
void LED_Commit(void);
|
||||
|
||||
|
|
17
src/main.c
17
src/main.c
|
@ -10,8 +10,25 @@ int main(void)
|
|||
|
||||
LED_Init();
|
||||
|
||||
int ct = 0;
|
||||
uint8_t *data = (uint8_t*)LED_PixelData;
|
||||
while(1)
|
||||
{
|
||||
if(LED_FrameFlag)
|
||||
{
|
||||
LED_FrameFlag = false;
|
||||
data[ct]++;
|
||||
LED_Commit();
|
||||
if(data[ct] == 255)
|
||||
{
|
||||
ct += 3;
|
||||
if(ct >= LED_COLUMNS * LED_ROWS)
|
||||
{
|
||||
ct -= LED_COLUMNS * LED_ROWS;
|
||||
ct += 1;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return 0;
|
||||
|
|
Loading…
Reference in a new issue