Allwinner R128 SDK HAL Module Development Guide PWM

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Allwinner R128 SDK HAL Module Development Guide PWM [Copy link]

 

# PWM ## Module Introduction Pulse Width Modulation (PWM) is a method of digitally encoding the level of an analog signal. By using a high-resolution counter, the duty cycle of a square wave is modulated to encode the level of a specific analog signal. PWM has the following features: - Supports pulse (number of pulses can be configured), period and complementary pair output; - Supports capture input; - With programmable dead zone generator, dead zone time can be controlled; - 0-24M/100M output frequency range, 0%-100% adjustable duty cycle, minimum resolution 1/65536; - Supports interrupt generation for PWM output and capture input; - Supports PWM group mode, and the starting phase of each channel in the same group can be configured. ## The module configuration path is as follows: ``` Kernel Setup ---> Drivers Setup ---> SoC HAL Drivers ---> pwm devices ---> [*] enable pwm driver ``` ## Source code structure```c rtos-hal/ |--hal/source/pwm/hal_pwm.c // hal layer interface code|--include/hal/sunxi_hal_pwm.h // header file``` ## Module interface description header file```c #include<sunxi_hal_pwm.h> ``` ### Return value enumeration ```c typedef enum { HAL_PWM_STATUS_ERROR_PARAMETER = -3, HAL_PWM_STATUS_ERROR_CHANNEL = -2, HAL_PWM_STATUS_ERROR = -1, HAL_PWM_STATUS_OK = 0 } hal_pwm_status_t; ``` ### PWM initialization interface PWM module initialization, mainly completes clk initialization Function prototype: ```c pwm_status_t hal_pwm_init(void) ``` Parameter: - Return value: - 0: success - Negative number: failure ### PWM channel configuration interface configures a channel of the PWM module, including period, duty cycle and polarity Function prototype: ```c pwm_status_t hal_pwm_control(int channel, struct pwm_config *config_pwm) ``` Parameter: - channel Represents the channel number - config_pwm represents the configuration parameters of the channel Return value: - 0: Success - Negative number: Failure### PWM channel enable interface Enable a channel of the PWM module Function prototype: ```c void hal_pwm_enable_controller(uint32_t channel_in) ``` Parameter: - channel_in represents the channel number Return value: - None### PWM deinitialization interface PWM module deinitialization, mainly close clk Function prototype: ```c pwm_status_t hal_pwm_deinit(void) ``` Parameter: - None Return value: - 0: Success - Negative number: Failure## Module usage example```c #include<stdio.h> #include <stdlib.h> #include<stdint.h> #include<string.h> #include<unistd.h> #include <hal_log.h> #include<hal_cmd.h> #include<sunxi_hal_pwm.h> #if defined(CONFIG_ARCH_DSP) #include <delay.h> #define sleep(sec) msleep(sec * 1000) #endif #ifndef printfFromISR #define printfFromISR printf #endif static int cmd_test_pwm(int argc, char **argv) { struct pwm_config *config; uint8_t port; //uint8_t ns; int period, duty; if (argc < 4) { hal_log_info("Usage: pwm port | duty | period\n"); return -1; } hal_log_info("Run pwm hal layer test case\n"); port = strtol(argv[1], NULL, 0); hal_log_info("port = %d", port); duty = strtoul(argv[2], NULL, 0); period = strtoul(argv[3], NULL, 0); config = (struct pwm_config *)malloc(sizeof(struct pwm_config)); config->duty_ns = duty; config->period_ns = period; config->polarity= PWM_POLARITY_NORMAL; hal_log_info("duty_ns = %d \n", config->duty_ns); hal_log_info("period_ns = %d \n", config->period_ns); hal_log_info("polarity = %d \n", config->polarity); hal_pwm_init(); hal_pwm_control(port, config); hal_log_info("control pwm test finish\n"); return 0; } FINSH_FUNCTION_EXPORT_CMD(cmd_test_pwm, hal_pwm, pwm hal APIs tests) static int cmd_release_pwm_channel(int argc, char **argv) { struct pwm_config *config; uint8_t port; uint8_t ns; ulong period, duty; if (argc < 2) { hal_log_info("Usage: pwm port\n"); return -1; } hal_log_info("Run close pwm channel test case\n"); port = strtol(argv[1], NULL, 0); hal_log_info("port = %d", port); hal_pwm_release(port); hal_log_info("release pwm channel finish\n"); return 0; } FINSH_FUNCTION_EXPORT_CMD(cmd_release_pwm_channel, hal_pwm_close, release pwm channel hal APIs tests) static void pwm_cap_callback(void* param) { hal_pwm_cap_info *info = (hal_pwm_cap_info *)param; printfFromISR("pwm%d capture callback, cnt is %d, period is %d, duty is %d\n", info->channel, info->cnt, info->period, info->duty); } hal_pwm_status_t pwm_capture_init(uint32_t channel) { hal_pwm_cap_enable(channel, pwm_cap_callback); return HAL_PWM_STATUS_OK; } hal_pwm_status_t pwm_capture_deinit(uint32_t channel) { hal_pwm_cap_disable(channel); return HAL_PWM_STATUS_OK; } void cmd_pwm_capture_help(void) { printf("pwm capture test, stop capture after 10s\n"); printf("usage: pwm_capture_test<channel>\n"); printf("\t<channel>: 0 ~ 15\n"); printf("eg: pwm_capture_test 0, pwm0 capture function\n"); } int cmd_pwm_capture(int argc, char *argv[]) { int count = 0; if (argc != 2 || atoi(argv[1]) > 15) { cmd_pwm_capture_help(); return -1; } /* capture setting */ pwm_capture_init(atoi(argv[1])); for(count = 0; count < 10; count++) { sleep(1); } /* disable */ pwm_capture_deinit(atoi(argv[1])); printf("[%s]: pwm stop capture ssd\n", __func__); return 0; } FINSH_FUNCTION_EXPORT_CMD(cmd_pwm_capture, pwm_capture_test, pwm capture test) ``` </channel></channel></delay.h></sunxi_hal_pwm.h></hal_cmd.h></hal_log.h></unistd.h></string.h></stdint.h></stdlib.h></stdio.h></sunxi_hal_pwm.h>

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With programmable dead zone generator, dead zone time is controllable;
0-24M/100M output frequency range, 0%-100% duty cycle adjustable, minimum resolution 1/65536;