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/* Megumin LED display firmware
* Copyright (C) 2018 Sebastian Götte <code@jaseg.net>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "adc.h"
#include "serial.h"
#include <stdbool.h>
#include <stdlib.h>
#include <assert.h>
static struct __attribute__((__packed__)) hl_adc_pkt {
struct ll_pkt ll;
uint16_t seq;
volatile uint16_t data[32];
} adc_pkt[2];
static uint16_t current_seq = 0;
static int current_buf = 0;
static void adc_dma_init(void);
static void adc_timer_init(int psc, int ivl);
static void adc_dma_launch(void);
/* Mode that can be used for debugging */
void adc_configure_scope_mode(int sampling_interval_ns) {
adc_dma_init();
/* Clock from PCLK/4 instead of the internal exclusive high-speed RC oscillator. */
ADC1->CFGR2 = (2<<ADC_CFGR2_CKMODE_Pos); /* Use PCLK/4=12MHz */
/* Sampling time 239.5 ADC clock cycles -> total conversion time 38.5us*/
ADC1->SMPR = (7<<ADC_SMPR_SMP_Pos);
/* Setup DMA and triggering */
/* Trigger from TIM1 TRGO */
ADC1->CFGR1 = ADC_CFGR1_DMAEN | ADC_CFGR1_DMACFG | (2<<ADC_CFGR1_EXTEN_Pos) | (1<<ADC_CFGR1_EXTSEL_Pos);
ADC1->CHSELR = ADC_CHSELR_CHSEL2;
/* Perform self-calibration */
ADC1->CR |= ADC_CR_ADCAL;
while (ADC1->CR & ADC_CR_ADCAL)
;
/* Enable conversion */
ADC1->CR |= ADC_CR_ADEN;
ADC1->CR |= ADC_CR_ADSTART;
/* An ADC conversion takes 1.1667us, so to be sure we don't get data overruns we limit sampling to every 1.5us.
Since we don't have a spare PLL to generate the ADC sample clock and re-configuring the system clock just for this
would be overkill we round to 250ns increments. The minimum sampling rate is about 60Hz due to timer resolution. */
int cycles = sampling_interval_ns > 1500 ? sampling_interval_ns/250 : 6;
if (cycles > 0xffff)
cycles = 0xffff;
adc_timer_init(12/*250ns/tick*/, cycles);
}
static void adc_dma_init() {
/* Configure DMA 1 Channel 1 to get rid of all the data */
DMA1_Channel1->CPAR = (unsigned int)&ADC1->DR;
DMA1_Channel1->CCR = (0<<DMA_CCR_PL_Pos);
DMA1_Channel1->CCR |=
(1<<DMA_CCR_MSIZE_Pos) /* 16 bit */
| (1<<DMA_CCR_PSIZE_Pos) /* 16 bit */
| DMA_CCR_MINC
| DMA_CCR_TCIE; /* Enable transfer complete interrupt. */
/* triggered on half-transfer and on transfer completion. We use this to send out the ADC data and to trap into GDB. */
NVIC_EnableIRQ(DMA1_Channel1_IRQn);
NVIC_SetPriority(DMA1_Channel1_IRQn, 2<<5);
adc_dma_launch();
}
void adc_dma_launch() {
DMA1_Channel1->CCR &= ~DMA_CCR_EN; /* Disable channel */
current_buf = !current_buf;
DMA1_Channel1->CMAR = (unsigned int)&(adc_pkt[current_buf].data);
DMA1_Channel1->CNDTR = ARRAY_LEN(adc_pkt[current_buf].data);
DMA1_Channel1->CCR |= DMA_CCR_EN; /* Enable channel */
}
static void adc_timer_init(int psc, int ivl) {
TIM1->BDTR = TIM_BDTR_MOE; /* MOE is needed even though we only "output" a chip-internal signal TODO: Verify this. */
TIM1->CCMR2 = (6<<TIM_CCMR2_OC4M_Pos); /* PWM Mode 1 to get a clean trigger signal */
TIM1->CCER = TIM_CCER_CC4E; /* Enable capture/compare unit 4 connected to ADC */
TIM1->CCR4 = 1; /* Trigger at start of timer cycle */
/* Set prescaler and interval */
TIM1->PSC = psc-1;
TIM1->ARR = ivl-1;
/* Preload all values */
TIM1->EGR |= TIM_EGR_UG;
TIM1->CR1 = TIM_CR1_ARPE;
/* And... go! */
TIM1->CR1 |= TIM_CR1_CEN;
}
/* This acts as a no-op that provides a convenient point to set a breakpoint for the debug scope logic */
static void gdb_dump(void) {
}
void DMA1_Channel1_IRQHandler(void) {
uint32_t isr = DMA1->ISR;
/* Clear the interrupt flag */
DMA1->IFCR |= DMA_IFCR_CGIF1;
adc_dma_launch();
gdb_dump();
adc_pkt[!current_buf].seq = current_seq++;
/* Ignore return value since we can't do anything here. Overruns are logged in serial.c. */
usart_send_packet_nonblocking(&adc_pkt[!current_buf].ll, sizeof(adc_pkt[!current_buf]));
/*
static int debug_buf_pos = 0;
if (st->sync) {
if (debug_buf_pos < NCH) {
debug_buf_pos = NCH;
} else {
adc_buf[debug_buf_pos++] = symbol;
if (debug_buf_pos >= sizeof(adc_buf)/sizeof(adc_buf[0])) {
debug_buf_pos = 0;
st->sync = 0;
gdb_dump();
for (int i=0; i<sizeof(adc_buf)/sizeof(adc_buf[0]); i++)
adc_buf[i] = -255;
}
}
}
*/
}
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