fruchti/inverse_thermal_camera
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Use DMA for SPI

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This commit is contained in:
fruchti 2018-08-04 08:21:48 +02:00
parent c695969e59
commit 17962b29ce
2 changed files with 25 additions and 11 deletions
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2
build-number.txt
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@ -1 +1 @@
124
138

34
src/ltp1245.c
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@ -60,6 +60,7 @@ static void InitDataLines(void)
RCC->APB2ENR |= RCC_APB2ENR_AFIOEN;
RCC->APB1ENR |= RCC_APB1ENR_SPI2EN;
RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;
RCC->AHBENR |= RCC_AHBENR_DMA1EN;
TIM2->PSC = 719; // Each tick corresponds to ten microseconds
TIM2->ARR = 201; // 2 milliseconds
@ -91,6 +92,12 @@ static void InitDataLines(void)
SPI2->CR1 = SPI_CR1_BIDIMODE | SPI_CR1_BIDIOE | SPI_CR1_SPE | SPI_CR1_MSTR
| SPI_CR1_BR_2;
SPI2->CR2 = SPI_CR2_TXDMAEN;
// SPI2_TX <-> DMA1_Channel5
DMA1_Channel5->CCR = DMA_CCR_MINC | DMA_CCR_TCIE | DMA_CCR_DIR;
DMA1_Channel5->CPAR = (uint32_t)&(SPI2->DR);
NVIC_EnableIRQ(DMA1_Channel5_IRQn);
}
static void InitThermistor(void)
@ -158,15 +165,12 @@ void ActivateHead(int mask)
static void SendLine(uint8_t *line)
{
for(int i = 0; i < LINEWIDTH / 8; i++)
{
while(~SPI2->SR & SPI_SR_TXE);
*((volatile uint8_t*)(&SPI2->DR)) = line[i];
}
while(SPI2->SR & SPI_SR_BSY);
GPIOB->BSRR = (1 << PIN_LATCH);
for(volatile int i = 0; i < 1000; i++);
GPIOB->BRR = (1 << PIN_LATCH);
// Wait for previous transfer
while(DMA1_Channel5->CNDTR);
DMA1_Channel5->CCR &= ~DMA_CCR_EN;
DMA1_Channel5->CMAR = (uint32_t)line;
DMA1_Channel5->CNDTR = LINEWIDTH / 8;
DMA1_Channel5->CCR |= DMA_CCR_EN;
}
// Main state machine states
@ -281,7 +285,7 @@ static State_t State_Idle(void)
void LTP1245_Print(void)
{
PrintLines = LTP1245_BUFFER_LINES * 20;
PrintLines = LTP1245_BUFFER_LINES * 5;
CurrentBufferLine = 0;
Printing = true;
}
@ -420,4 +424,14 @@ void ADC1_2_IRQHandler(void)
// a pulse with in microseconds
PulseWidth = (285 * 178 - (int)(1000 * 178 * 0.003135) * (temp - 25))
/ (int)((5 * 1.4 - 2.9) * (5 * 1.4 - 2.9));
}
void DMA1_Channel5_IRQHandler(void)
{
DMA1->IFCR = DMA_IFCR_CTCIF5;
// Generate LATCH pulse
GPIOB->BSRR = (1 << PIN_LATCH);
for(volatile int i = 0; i < 1000; i++);
GPIOB->BRR = (1 << PIN_LATCH);
}