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I found there's strength PWM output on 20737S, could someone help to check?
I test again with pwm_tones demo project in SDK2.0, and get the following signal:
The 1st picture is a cycle of PWM signal, and the 2nd picture is a zoom out that shows there is another "big" cycle to generate.
The output tone is periodically "bi", "bi" .... around around 1 sec. period. I think this is not the normal PWM. Then I test following simple code again in Hello project, but get similar strange result.
aclk_configure(512000, ACLK1, ACLK_FREQ_24_MHZ);
pwm_start(0, PMU_CLK, 0x2FF, 0x200);
gpio_configurePin(26 >> 4, 26 & 0x0F, GPIO_OUTPUT_ENABLE, 0);
Solved! Go to Solution.
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You can also use LHL_CLK instead of PMU_CLK to have a PWM output even when the device is in sleep mode.
But be aware that LHL_CLK has a lower frequency than PMU_CLK.
Snippet from include/Drivers/pwm.h:
/// Clock used for PWM. When LHL_CLK is set, 128 KHz is used. When PMU_CLK is set, 1 MHz or 8 MHz.
typedef enum
{
LHL_CLK,
PMU_CLK
} PwmClockType;
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20737S seems to be in sleep mode between tones.
Please try devlpm_registerForLowPowerQueries() and return 0 at the registered function.
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You can also use LHL_CLK instead of PMU_CLK to have a PWM output even when the device is in sleep mode.
But be aware that LHL_CLK has a lower frequency than PMU_CLK.
Snippet from include/Drivers/pwm.h:
/// Clock used for PWM. When LHL_CLK is set, 128 KHz is used. When PMU_CLK is set, 1 MHz or 8 MHz.
typedef enum
{
LHL_CLK,
PMU_CLK
} PwmClockType;