From 091582c446319fe4a79154153ece5372b2faec83 Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Wed, 1 May 2013 08:58:17 -0700 Subject: [PATCH 1/1] altos: Use SYSTICK on STM32L It's probably more power efficient than using one of the timers, and it's certainly easier to configure. Signed-off-by: Keith Packard --- src/stm/ao_arch.h | 1 + src/stm/ao_timer.c | 40 +++++++++------------------------------- src/stm/registers.ld | 2 ++ src/stm/stm32l.h | 18 ++++++++++++++++++ 4 files changed, 30 insertions(+), 31 deletions(-) diff --git a/src/stm/ao_arch.h b/src/stm/ao_arch.h index 007f7e2e..27a942f2 100644 --- a/src/stm/ao_arch.h +++ b/src/stm/ao_arch.h @@ -99,6 +99,7 @@ extern const uint32_t ao_radio_cal; #define AO_HCLK (AO_SYSCLK / AO_AHB_PRESCALER) #define AO_PCLK1 (AO_HCLK / AO_APB1_PRESCALER) #define AO_PCLK2 (AO_HCLK / AO_APB2_PRESCALER) +#define AO_SYSTICK (AO_HCLK / 8) #if AO_APB1_PRESCALER == 1 #define AO_TIM23467_CLK AO_PCLK1 diff --git a/src/stm/ao_timer.c b/src/stm/ao_timer.c index 8b7c2327..5976eb3f 100644 --- a/src/stm/ao_timer.c +++ b/src/stm/ao_timer.c @@ -31,14 +31,9 @@ volatile __data uint8_t ao_data_interval = 1; volatile __data uint8_t ao_data_count; #endif -void -ao_debug_out(char c); - - -void stm_tim6_isr(void) +void stm_systick_isr(void) { - if (stm_tim6.sr & (1 << STM_TIM67_SR_UIF)) { - stm_tim6.sr = 0; + if (stm_systick.csr & (1 << STM_SYSTICK_CSR_COUNTFLAG)) { ++ao_tick_count; #if HAS_TASK_QUEUE if (ao_task_alarm_tick && (int16_t) (ao_tick_count - ao_task_alarm_tick) >= 0) @@ -81,33 +76,16 @@ ao_timer_set_adc_interval(uint8_t interval) #define TIMER_10kHz ((AO_PCLK1 * TIMER_23467_SCALER) / 10000) +#define SYSTICK_RELOAD (AO_SYSTICK / 100 - 1) + void ao_timer_init(void) { - stm_nvic_set_enable(STM_ISR_TIM6_POS); - stm_nvic_set_priority(STM_ISR_TIM6_POS, AO_STM_NVIC_CLOCK_PRIORITY); - - /* Turn on timer 6 */ - stm_rcc.apb1enr |= (1 << STM_RCC_APB1ENR_TIM6EN); - - stm_tim6.psc = TIMER_10kHz; - stm_tim6.arr = 99; - stm_tim6.cnt = 0; - - /* Enable update interrupt */ - stm_tim6.dier = (1 << STM_TIM67_DIER_UIE); - - /* Poke timer to reload values */ - stm_tim6.egr |= (1 << STM_TIM67_EGR_UG); - - stm_tim6.cr2 = (STM_TIM67_CR2_MMS_RESET << STM_TIM67_CR2_MMS); - - /* And turn it on */ - stm_tim6.cr1 = ((0 << STM_TIM67_CR1_ARPE) | - (0 << STM_TIM67_CR1_OPM) | - (1 << STM_TIM67_CR1_URS) | - (0 << STM_TIM67_CR1_UDIS) | - (1 << STM_TIM67_CR1_CEN)); + stm_systick.rvr = SYSTICK_RELOAD; + stm_systick.cvr = 0; + stm_systick.csr = ((1 << STM_SYSTICK_CSR_ENABLE) | + (1 << STM_SYSTICK_CSR_TICKINT) | + (STM_SYSTICK_CSR_CLKSOURCE_HCLK_8 << STM_SYSTICK_CSR_CLKSOURCE)); } void diff --git a/src/stm/registers.ld b/src/stm/registers.ld index 95a86e35..8318c75a 100644 --- a/src/stm/registers.ld +++ b/src/stm/registers.ld @@ -44,6 +44,8 @@ stm_tim4 = 0x40000800; stm_tim3 = 0x40000400; stm_tim2 = 0x40000000; +stm_systick = 0xe000e010; + stm_nvic = 0xe000e100; stm_scb = 0xe000ed00; diff --git a/src/stm/stm32l.h b/src/stm/stm32l.h index 1d636037..5c0748a6 100644 --- a/src/stm/stm32l.h +++ b/src/stm/stm32l.h @@ -811,6 +811,24 @@ extern struct stm_lcd stm_lcd; #define STM_LCD_CLR_UDDC (3) #define STM_LCD_CLR_SOFC (1) +/* The SYSTICK starts at 0xe000e010 */ + +struct stm_systick { + vuint32_t csr; + vuint32_t rvr; + vuint32_t cvr; + vuint32_t calib; +}; + +extern struct stm_systick stm_systick; + +#define STM_SYSTICK_CSR_ENABLE 0 +#define STM_SYSTICK_CSR_TICKINT 1 +#define STM_SYSTICK_CSR_CLKSOURCE 2 +#define STM_SYSTICK_CSR_CLKSOURCE_HCLK_8 0 +#define STM_SYSTICK_CSR_CLKSOURCE_HCLK 1 +#define STM_SYSTICK_CSR_COUNTFLAG 16 + /* The NVIC starts at 0xe000e100, so add that to the offsets to find the absolute address */ struct stm_nvic { -- 2.30.2