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RIOT/cpu/stm32/include/periph/cpu_timer.h
Marian Buschsieweke 7c0a4b8390
cpu/stm32/periph_timer: Support timers with channels != 4
The assumption that all STM32 timers have exactly four channels no
longer holds. E.g. the STM32L4 has the following general purpose timers:

- TIM2: 32 bit, 4 channels
- TIM15: 16 bit, 2 channels
- TIM16: 16 bit, 1 channel

Hence, a new field is added to the timer configuration to also contain
the number of timer channels. Due to alignment the `struct` previously
was padded by 16 bit, so adding another 8 bit field doesn't increase
its size.

For backward compatibility, a value of `0` is considered as alias for
`TIMER_CHANNEL_NUMOF` (or 4), so that the number of timer channels
only needs to be set when the timer is different from the typical 4
channel timer. This helps backward compatibility.
2023-05-30 12:55:29 +02:00

66 lines
1.5 KiB
C

/*
* Copyright (C) 2016 Freie Universität Berlin
* 2017 OTA keys S.A.
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup cpu_stm32
* @{
*
* @file
* @brief Timer CPU specific definitions for the STM32 family
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Vincent Dupont <vincent@otakeys.com>
*/
#ifndef PERIPH_CPU_TIMER_H
#define PERIPH_CPU_TIMER_H
#include <stdint.h>
#include "cpu.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief All STM timers have at most 4 capture-compare channels
*/
#define TIMER_CHANNEL_NUMOF (4U)
/**
* @brief The driver provides a relative set function
*/
#define PERIPH_TIMER_PROVIDES_SET
/**
* @brief Define a macro for accessing a timer channel
*/
#define TIM_CHAN(tim, chan) *(&dev(tim)->CCR1 + chan)
/**
* @brief Timer configuration
*/
typedef struct {
TIM_TypeDef *dev; /**< timer device */
uint32_t max; /**< maximum value to count to (16/32 bit) */
uint32_t rcc_mask; /**< corresponding bit in the RCC register */
uint8_t bus; /**< APBx bus the timer is clock from */
uint8_t irqn; /**< global IRQ channel */
uint8_t channel_numof; /**< number of channels, 0 is alias for
@ref TIMER_CHANNEL_NUMOF */
} timer_conf_t;
#ifdef __cplusplus
}
#endif
#endif /* PERIPH_CPU_TIMER_H */
/** @} */