Chapter 2. API Reference
enum dac_digi_convert_mode_t
DAC digital controller (DMA mode) work mode.
Values:
DAC_CONV_NORMAL
The data in the DMA buffer is simultaneously output to the enable channel of the DAC.
DAC_CONV_ALTER
The data in the DMA buffer is alternately output to the enable channel of the DAC.
DAC_CONV_MAX
2.2.3 General Purpose Timer
Introduction
The ESP32-S2 chip contains two hardware timer groups. Each group has two general-purpose hardware timer(s).
They are all 64-bit generic timers based on 16-bit pre-scalers and 64-bit up / down counters which are capable of
being auto-reloaded.
Functional Overview
The following sections of this document cover the typical steps to configure and operate a timer:
• Timer Initialization - covers which parameters should be set up to get the timer working, and also what specific
functionality is provided depending on the timer configuration.
• Timer Control - describes how to read a timer’s value, pause or start a timer, and change how it operates.
• Alarms - shows how to set and use alarms.
• Interrupts- explains how to use interrupt callbacks.
Timer Initialization The two ESP32-S2 timer groups, with two timer(s) in each, provide the total of four individual
timers for use. An ESP32-S2 timer group should be identified using timer_group_t. An individual timer in a
group should be identified with timer_idx_t.
First of all, the timer should be initialized by calling the function timer_init() and passing a structure
timer_config_t to it to define how the timer should operate. In particular, the following timer parameters
can be set:
• Clock Source: Select the clock source, which together with the Divider define the resolution of the working
timer.
• Divider: Sets how quickly the timer’s counter is“ticking”. The setting divider is used as a divisor of the
clock source that by default is APB_CLK running at 80 MHz. For more information of APB_CLK frequency,
please check ESP32-S2 Technical Reference Manual > Reset and Clock [PDF] chapter for more details.
• Mode: Sets if the counter should be incrementing or decrementing. It can be defined using counter_dir
by selecting one of the values from timer_count_dir_t.
• Counter Enable: If the counter is enabled, it will start incrementing / decrementing immediately after calling
timer_init(). You can change the behavior with counter_en by selecting one of the values from
timer_start_t.
• Alarm Enable: Can be set using alarm_en.
• Auto Reload: Sets if the counter should auto_reload the initial counter value on the timer’s alarm or
continue incrementing or decrementing.
To get the current values of the timer’s settings, use the function timer_get_config().
Timer Control Once the timer is enabled, its counter starts running. To enable the timer, call the function
timer_init() with counter_en set to true, or call timer_start(). You can specify the timer’s
initial counter value by calling timer_set_counter_value(). To check the timer’s current value, call
timer_get_counter_value() or timer_get_counter_time_sec().
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