DS18B20: Better timer magic

diff --git a/lib/ds18b20.c b/lib/ds18b20.c
index 30ad08e13eaec5a86d6cbac85a3d9c57e7a9ab5c..02a62cf0e31b8b483c5d8c5d1396ad2c5e0a4e1e 100644 (file)
--- a/lib/ds18b20.c
+++ b/lib/ds18b20.c
@@ -81,11 +81,9 @@ static bool ds_reset(void)
        }
 
        // Pull line down and start timer
-       cm_disable_interrupts();
        timer_generate_event(DS_TIMER, TIM_EGR_UG);
-       timer_enable_counter(DS_TIMER);
        timer_set_oc_mode(DS_TIMER, TIM_OC2, TIM_OCM_INACTIVE);
-       cm_enable_interrupts();
+       timer_enable_counter(DS_TIMER);
 
        // Wait until the timer expires
        while (timer_is_counter_enabled(DS_TIMER))
@@ -114,12 +112,9 @@ static void ds_send_bit(bool bit)
        timer_set_period(DS_TIMER, 99);                         // Each write slot takes 100 μs
        timer_set_oc_mode(DS_TIMER, TIM_OC2, TIM_OCM_FORCE_HIGH);
        timer_set_oc_value(DS_TIMER, TIM_OC2, (bit ? 3 : 89));  // 1: 3μs pulse, 0: 89μs pulse
-       cm_disable_interrupts();
-       // XXX: On STM32F1, we must configure the OC channel _after_ we enable the counter,
-       // otherwise OC triggers immediately. Reasons?
-       timer_enable_counter(DS_TIMER);
+       timer_generate_event(DS_TIMER, TIM_EGR_UG);
        timer_set_oc_mode(DS_TIMER, TIM_OC2, TIM_OCM_INACTIVE);
-       cm_enable_interrupts();
+       timer_enable_counter(DS_TIMER);
        while (timer_is_counter_enabled(DS_TIMER))
                ;
 }
@@ -142,10 +137,9 @@ static bool ds_recv_bit(void)
        dma_set_number_of_data(DS_DMA, DS_DMA_CH, 1);
        dma_enable_channel(DS_DMA, DS_DMA_CH);
        timer_set_oc_mode(DS_TIMER, TIM_OC2, TIM_OCM_FORCE_HIGH);
-       cm_disable_interrupts();
-       timer_enable_counter(DS_TIMER);
+       timer_generate_event(DS_TIMER, TIM_EGR_UG);
        timer_set_oc_mode(DS_TIMER, TIM_OC2, TIM_OCM_INACTIVE);
-       cm_enable_interrupts();
+       timer_enable_counter(DS_TIMER);
        while (timer_is_counter_enabled(DS_TIMER))
                ;
        // DEBUG2("XXX %08x\n", ds_dma_buffer);