diff options
Diffstat (limited to 'src/lib/timers.c')
| -rw-r--r-- | src/lib/timers.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/src/lib/timers.c b/src/lib/timers.c new file mode 100644 index 0000000..401b267 --- /dev/null +++ b/src/lib/timers.c @@ -0,0 +1,114 @@ +#include "stm32f10x_rcc.h" +#include "wiring.h" +#include "timers.h" +#include "util.h" + +typedef struct { + volatile uint16_t CR1; + uint16_t RESERVED0; + volatile uint16_t CR2; + uint16_t RESERVED1; + volatile uint16_t SMCR; + uint16_t RESERVED2; + volatile uint16_t DIER; + uint16_t RESERVED3; + volatile uint16_t SR; + uint16_t RESERVED4; + volatile uint16_t EGR; + uint16_t RESERVED5; + volatile uint16_t CCMR1; + uint16_t RESERVED6; + volatile uint16_t CCMR2; + uint16_t RESERVED7; + volatile uint16_t CCER; + uint16_t RESERVED8; + volatile uint16_t CNT; + uint16_t RESERVED9; + volatile uint16_t PSC; + uint16_t RESERVED10; + volatile uint16_t ARR; + uint16_t RESERVED11; + volatile uint16_t RCR; + uint16_t RESERVED12; + volatile uint16_t CCR1; + uint16_t RESERVED13; + volatile uint16_t CCR2; + uint16_t RESERVED14; + volatile uint16_t CCR3; + uint16_t RESERVED15; + volatile uint16_t CCR4; + uint16_t RESERVED16; + volatile uint16_t BDTR; // Not used in general purpose timers + uint16_t RESERVED17; // Not used in general purpose timers + volatile uint16_t DCR; + uint16_t RESERVED18; + volatile uint16_t DMAR; + uint16_t RESERVED19; +} Timer; + +void timer_init(uint8_t timer_num, uint16_t prescale) { + Timer *timer; + uint32_t is_advanced = 0; + + ASSERT(timer_num > 0 && timer_num <= 4); + + switch(timer_num) { + case 1: + timer = (Timer*)TIMER1_BASE; + RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE); + is_advanced = 1; + break; + case 2: + timer = (Timer*)TIMER2_BASE; + RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); + break; + case 3: + timer = (Timer*)TIMER3_BASE; + RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); + break; + case 4: + timer = (Timer*)TIMER4_BASE; + RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE); + break; + } + + timer->CR1 = ARPE; // No clock division + // Do not buffer auto-reload preload + // Edge aligned + // Upcounter + // Do not stop counter at update event + // Update events enabled (etc, see bits [1:2]) + // Counter disabled for now + + timer->PSC = prescale; // Prescaling by prescale (duh) + timer->ARR = 0xFFFF; // Max reload cont + + /* initialize all the channels to 50% duty cycle, + * TODO: none of them actually get output unless the gpio pin + * is set, this will probably consume a bit more power but + * we'll worry about that later. */ + timer->CCR1 = 0x8FFF; // PWM start value + timer->CCMR1 |= 0x68; // PWM mode 1, enable preload register. + timer->CCER |= 0x001; // enable ch + + timer->CCR2 = 0x8FFF; // PWM start value + timer->CCMR1 |= (0x68 << 8);// PWM mode 1, enable preload register. + timer->CCER |= 0x010; // enable ch + + timer->CCR3 = 0x8FFF; // PWM start value + timer->CCMR2 |= 0x68; // PWM mode 1, enable preload register. + timer->CCER |= 0x100; // enable ch + + timer->CCR4 = 0x8FFF; // PWM start value + timer->CCMR2 |= (0x68 << 8);// PWM mode 1, enable preload register. + timer->CCER |= 0x1000; // enable ch + + /* Advanced timer? */ + if (is_advanced) { + timer->BDTR = 0x8000; // moe enable + } + + timer->DIER = 0; // disable update interrupt + timer->EGR = 1; // Initialize update event and shadow registers + timer->CR1 |= 1; // Enable timer +} |