--- /dev/null
+/*
+ * Copyright © 2024 Keith Packard <keithp@keithp.com>
+ *
+ * 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 2 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, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+#include <ao.h>
+#include <ao_fast_timer.h>
+
+static void (*ao_fast_timer_callback[AO_FAST_TIMER_MAX])(void);
+static uint8_t ao_fast_timer_count;
+static uint8_t ao_fast_timer_users;
+
+#if AO_FAST_TIMER == 1
+
+# define AO_FAST_TIMER_TYPE 18
+# define stm_tim stm_tim1
+# define stm_tim_isr stm_tim1_up_isr
+# define STM_ISR_TIM_POS STM_ISR_TIM1_UP_POS
+# define STM_RCC_APBENR_TIMEN STM_RCC_APB2ENR_TIM1EN
+
+#elif AO_FAST_TIMER == 2
+
+# define AO_FAST_TIMER_TYPE 234
+# define stm_tim stm_tim2
+# define stm_tim_isr stm_tim2_isr
+# define STM_ISR_TIM_POS STM_ISR_TIM2_POS
+# define STM_RCC_APBENR_TIMEN STM_RCC_APB1ENR_TIM2EN
+
+#elif AO_FAST_TIMER == 3
+
+# define AO_FAST_TIMER_TYPE 234
+# define stm_tim stm_tim3
+# define stm_tim_isr stm_tim3_isr
+# define STM_ISR_TIM_POS STM_ISR_TIM3_POS
+# define STM_RCC_APBENR_TIMEN STM_RCC_APB1ENR_TIM3EN
+
+#elif AO_FAST_TIMER == 4
+
+# define AO_FAST_TIMER_TYPE 234
+# define stm_tim stm_tim4
+# define stm_tim_isr stm_tim4_isr
+# define STM_ISR_TIM_POS STM_ISR_TIM4_POS
+# define STM_RCC_APBENR_TIMEN STM_RCC_APB1ENR_TIM4EN
+
+#else
+#error AO_FAST_TIMER
+#endif
+
+#if AO_FAST_TIMER_TYPE == 18
+
+#define STM_TIM_CR1(cen) ((0 << STM_TIM18_CR1_CKD) | \
+ (0 << STM_TIM18_CR1_ARPE) | \
+ (0 << STM_TIM18_CR1_CMS) | \
+ (0 << STM_TIM18_CR1_DIR) | \
+ (0 << STM_TIM18_CR1_OPM) | \
+ (1 << STM_TIM18_CR1_URS) | \
+ (0 << STM_TIM18_CR1_UDIS) | \
+ ((cen) << STM_TIM18_CR1_CEN))
+#define STM_TIM_SR_UIF STM_TIM18_SR_UIF
+#define STM_TIM_DIER_UIE STM_TIM18_DIER_UIE
+#define STM_TIM_EGR_UG STM_TIM18_EGR_UG
+#define STM_TIM_CR2_MMS STM_TIM18_CR2_MMS
+#define STM_TIM_CR2_MMS_RESET STM_TIM18_CR2_MMS_RESET
+
+#define AO_TIM_PCLK AO_PCLK2
+
+/*
+ * According to the STM clock-configuration, timers 18 run
+ * twice as fast as the APB2 clock *if* the APB2 prescaler
+ * is greater than 1.
+ */
+
+#if AO_APB2_PRESCALER > 1
+#define AO_TIM_SCALER 2
+#else
+#define AO_TIM_SCALER 1
+#endif
+
+#define STM_RCC_APB_TIM stm_rcc.apb2enr
+
+#elif AO_FAST_TIMER_TYPE == 234
+
+#define STM_TIM_CR1(cen) ((STM_TIM234_CR1_CKD_1 << STM_TIM234_CR1_CKD) | \
+ (0 << STM_TIM234_CR1_ARPE) | \
+ (STM_TIM234_CR1_CMS_EDGE << STM_TIM234_CR1_CMS) | \
+ (0 << STM_TIM234_CR1_DIR) | \
+ (0 << STM_TIM234_CR1_OPM) | \
+ (0 << STM_TIM234_CR1_URS) | \
+ (0 << STM_TIM234_CR1_UDIS) | \
+ ((cen) << STM_TIM234_CR1_CEN)) \
+
+#define AO_TIM_PCLK AO_PCLK1
+
+/*
+ * According to the STM clock-configuration, timers 234 run
+ * twice as fast as the APB1 clock *if* the APB1 prescaler
+ * is greater than 1.
+ */
+
+#if AO_APB1_PRESCALER > 1
+#define AO_TIM_SCALER 2
+#else
+#define AO_TIM_SCALER 1
+#endif
+
+#define STM_TIM_SR_UIF STM_TIM234_SR_UIF
+#define STM_TIM_DIER_UIE STM_TIM234_DIER_UIE
+#define STM_TIM_EGR_UG STM_TIM234_EGR_UG
+#define STM_TIM_CR2_MMS STM_TIM234_CR2_MMS
+#define STM_TIM_CR2_MMS_RESET STM_TIM234_CR2_MMS_RESET
+
+#define STM_RCC_APB_TIM stm_rcc.apb1enr
+
+#endif
+
+static void
+ao_fast_timer_enable(void)
+{
+ stm_tim.cr1 = STM_TIM_CR1(1);
+}
+
+static void
+ao_fast_timer_disable(void)
+{
+ stm_tim.cr1 = STM_TIM_CR1(0);
+}
+
+void
+ao_fast_timer_on(void (*callback)(void))
+{
+ ao_fast_timer_callback[ao_fast_timer_count] = callback;
+ if (!ao_fast_timer_count++)
+ ao_fast_timer_enable();
+}
+
+void
+ao_fast_timer_off(void (*callback)(void))
+{
+ uint8_t n;
+
+ for (n = 0; n < ao_fast_timer_count; n++)
+ if (ao_fast_timer_callback[n] == callback) {
+ for (; n < ao_fast_timer_count-1; n++) {
+ ao_fast_timer_callback[n] = ao_fast_timer_callback[n+1];
+ }
+ if (!--ao_fast_timer_count)
+ ao_fast_timer_disable();
+ break;
+ }
+}
+
+void stm_tim_isr(void)
+{
+ uint8_t i;
+ if (stm_tim.sr & (1 << STM_TIM_SR_UIF)) {
+ stm_tim.sr = 0;
+
+ for (i = 0; i < ao_fast_timer_count; i++)
+ (*ao_fast_timer_callback[i])();
+ }
+}
+
+#ifndef FAST_TIMER_FREQ
+#define FAST_TIMER_FREQ 10000
+#endif
+
+#define TIMER_FAST ((AO_TIM_PCLK * AO_TIM_SCALER) / FAST_TIMER_FREQ)
+
+void
+ao_fast_timer_init(void)
+{
+ if (!ao_fast_timer_users) {
+ stm_nvic_set_enable(STM_ISR_TIM_POS);
+ stm_nvic_set_priority(STM_ISR_TIM_POS, AO_STM_NVIC_CLOCK_PRIORITY);
+
+ /* Turn on timer 1 */
+ STM_RCC_APB_TIM |= (1 << STM_RCC_APBENR_TIMEN);
+
+ stm_tim.psc = TIMER_FAST;
+ stm_tim.arr = 9;
+ stm_tim.cnt = 0;
+
+ /* Enable update interrupt */
+ stm_tim.dier = (1 << STM_TIM_DIER_UIE);
+
+ /* Poke timer to reload values */
+ stm_tim.egr |= (1 << STM_TIM_EGR_UG);
+
+ stm_tim.cr2 = (STM_TIM_CR2_MMS_RESET << STM_TIM_CR2_MMS);
+ ao_fast_timer_disable();
+ }
+ if (ao_fast_timer_users == AO_FAST_TIMER_MAX)
+ ao_panic(AO_PANIC_FAST_TIMER);
+ ao_fast_timer_users++;
+}
+
projects / fw / altos / blobdiff