RT1064DVJ6B and PWMX signal issue

[frankk]

Hello,

we would like to use PWMX_03 (GPIO_AD_B0_13) signal of PWM1 and submodule 0. The problem is that we can only enable PWMX_0 (GPIO_AD_B0_02).

The next wierd thing is that it doesnt matter what pin is configured in pin_mux.c. I tried:

IOMUXC_GPIO_AD_B0_02_FLEXPWM1_PWMX00
IOMUXC_GPIO_AD_B0_03_FLEXPWM1_PWMX01
IOMUXC_GPIO_AD_B0_12_FLEXPWM1_PWMX02
IOMUXC_GPIO_AD_B0_13_FLEXPWM1_PWMX03
I tried it on rt1064 evalboard. Our board is already designed and we need PWMX03 (fix 50% duty cycle is ok)

Here is the whole picture:

I attached the picture for download in case you cannot read it.

[frankk · Accepted solution]

I solved it by myself. Attached you will find the code.

What I figured out: PWMX00 belongs to submodule0, PWMX01 belongs to submodule1 and PWMX03 belongs to submodule3. I assumed that FlexPWM1 corresponds to submodule0 and FlexPWM4 corresponds to submodule3. Obviously this is not the case. I think each FlexPWM module has four submodules. This is not mentioned in datasheet.

And by the way, I have never seen such bad datasheet. With this µC datasheet it is always the same, spending a lot of time to get such simple functions to work. Actually it needs one sentence or one better block diagram in datasheet.

Regards,

Frank

[EdwinHz]

Hi @frankk,

As you mention, the SDK’s PWM_SetupPwm API doesn’t include this channel by default. You would have to modify it manually to include PWM_OUTEN_PWMX_EN_SHIFT.

Keep in mind that the GPIO_AD_B0_13 is by default used for LPUART. If you want to use this pin, you must also first change its functionality. Let me know if this helps.

BR,

Edwin.

[frankk]

Hello,

Im still unable to get a pwm signal out of GPIO_AD_B0_13 (PWMX03). Attached you will find the picture and the pwm example code (minimal example).

I must correct my answer where I wrote that no matter pinmux setting is configured there is always a pwm signal at GPIO_AD_B0_02 (PWMX00). For instance: If I set PWMX00 in pinmux I can measure a pwm signal. When I change PWMX00 to PWMX01 I could still measure a pwm signal at PWMX00 pin. Changing the GPIO pin in pinmux without doing a power cycle this bahaviour occurs.

Nevertheless, only PWMX00 works properly. There is no PWM signal at GPIO_AD_B0_03 (PWMX01), GPIO_AD_B0_12 (PWMX02) or GPIO_AD_B0_13 (PWMX03).

I think there is no pwm signal routed to these pins chip internally.

Can anybody try the attached code and confirm it? 

Thank you in advance.

Regards,

Frank

Edit:

to be sure that this is really the pin (GPIO_AD_B0_13), I configured it to normal gpio and tried the following:

IOMUXC_SetPinMux(
IOMUXC_GPIO_AD_B0_13_GPIO1_IO13,
0U);

IOMUXC_SetPinConfig(IOMUXC_GPIO_AD_B0_13_GPIO1_IO13,
0x10B0u);

GPIO_PinInit(GPIO1, 13, &gpio_config_high);

GPIO_WritePinOutput(GPIO1, 13, 1);

GPIO_WritePinOutput(GPIO1, 13, 0);

GPIO_WritePinOutput(GPIO1, 13, 1);

GPIO is working properly, I can measure the signal goes high and low at J45 jumper.

[frankk]

Hi @EdwinHz ,

thank you for you reply. LPUART1 is disabled in my code.

This is my pinmux setting for pwmx03:

IOMUXC_SetPinMux(
IOMUXC_GPIO_AD_B0_13_FLEXPWM1_PWMX03, 0U);

IOMUXC_SetPinConfig(
IOMUXC_GPIO_AD_B0_13_FLEXPWM1_PWMX03, 0x10B0u);

And here the code line to enable pwmx output:

base->OUTEN |= ((uint16_t)1U << ((uint16_t)PWM_OUTEN_PWMX_EN_SHIFT + (uint16_t)kPWM_Module_0)); */A

Again there is really no pwm signal. As I mentioned before, to measure the pwm signal I disconnected LPUART1 RXD jumper on evalboard and connected the probe to this pinheader (I tried pin1 and pin2).

Only at GPIO_AD_B0_02 I can measure a pwm signal. And by the way no matter what signal is configured in pinmux. For instance if I set GPIO_AD_B0_13 or ..B0_12 or ..B0_02, immediately after enablling by */A there is only a pwm signal at GPIO_AD_B0_02. This is very strange behavior.

Do you have another idea for me please?