PWM in nrf5340 - blinky example fails to compile with SDK 2.7.0

[Repa]

Greetings,

trying to get PWM working with nrf5340. Unfortunately I am not able to even get the blinky PWM example compiled with the setup using SDK 2.7.0. The compile is ok nrf51822, so the environment should be in order.

The compilation log claims (for bl5340_dvk tried some other boards as well with no success):

In file included from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/toolchain/gcc.h:98,
                 from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/toolchain.h:50,
                 from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/kernel_includes.h:23,
                 from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/kernel.h:17,
                 from C:/Users/mattip-local/Projects/Nordic/Sandbox/blinky_pwm_ref/src/main.c:12:
C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/device.h:91:41: error: '__device_dts_ord_DT_N_ALIAS_pwm_led0_P_pwms_IDX_0_PH_ORD' undeclared here (not in a function)
   91 | #define DEVICE_NAME_GET(dev_id) _CONCAT(__device_, dev_id)
      |                                         ^~~~~~~~~
C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/toolchain/common.h:137:26: note: in definition of macro '_DO_CONCAT'
  137 | #define _DO_CONCAT(x, y) x ## y
      |                          ^
C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/device.h:91:33: note: in expansion of macro '_CONCAT'
   91 | #define DEVICE_NAME_GET(dev_id) _CONCAT(__device_, dev_id)
      |                                 ^~~~~~~
C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/device.h:228:37: note: in expansion of macro 'DEVICE_NAME_GET'
  228 | #define DEVICE_DT_NAME_GET(node_id) DEVICE_NAME_GET(Z_DEVICE_DT_DEV_ID(node_id))
      |                                     ^~~~~~~~~~~~~~~
C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/device.h:245:34: note: in expansion of macro 'DEVICE_DT_NAME_GET'
  245 | #define DEVICE_DT_GET(node_id) (&DEVICE_DT_NAME_GET(node_id))
      |                                  ^~~~~~~~~~~~~~~~~~
C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/drivers/pwm.h:260:24: note: in expansion of macro 'DEVICE_DT_GET'
  260 |                 .dev = DEVICE_DT_GET(DT_PWMS_CTLR_BY_IDX(node_id, idx)),       \
      |                        ^~~~~~~~~~~~~
C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/drivers/pwm.h:328:34: note: in expansion of macro 'PWM_DT_SPEC_GET_BY_IDX'
  328 | #define PWM_DT_SPEC_GET(node_id) PWM_DT_SPEC_GET_BY_IDX(node_id, 0)
      |                                  ^~~~~~~~~~~~~~~~~~~~~~
C:/Users/mattip-local/Projects/Nordic/Sandbox/blinky_pwm_ref/src/main.c:17:44: note: in expansion of macro 'PWM_DT_SPEC_GET'
   17 | static const struct pwm_dt_spec pwm_led0 = PWM_DT_SPEC_GET(DT_ALIAS(pwm_led0));
      |                                            ^~~~~~~~~~~~~~~
In file included from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/arch/arm/arch.h:20,
                 from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/arch/cpu.h:19,
                 from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/kernel_includes.h:36:
C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/devicetree.h:240:32: error: 'DT_N_ALIAS_pwm_led0_P_pwms_IDX_0_VAL_channel' undeclared here (not in a function)

What is wrong here?

[Hieu]

Hi Repa,

This line of code means that the sample expect a DeviceTree node named pwm_led0:
https://github.com/nrfconnect/sdk-zephyr/blob/v3.6.99-ncs2/samples/basic/blinky_pwm/src/main.c#L17

However, there is no such node in the bl5340_dvk board.
https://github.com/nrfconnect/sdk-zephyr/tree/v3.6.99-ncs2/boards/lairdconnect/bl5340_dvk

The sample will compile fine with the nrf5340dk/nrf5340/cpuapp target, which has such a node.
https://github.com/nrfconnect/sdk-zephyr/blob/v3.6.99-ncs2/boards/nordic/nrf5340dk/nrf5340_cpuapp_common.dtsi#L42-L47

Note that the sample is setup to overlay the nRF5340 DK board file so that the pwm_led0 device runs off of software emulated PWM rather than peripheral PWM. This is because of a specific setup in the sample.
https://github.com/nrfconnect/sdk-zephyr/commit/993cb302403634f7cbca22e0c72aebc18923eb26
The peripheral PWM works normally with a different period and duty cycle configurations.

If you need more information on DeviceTree and overlay, I recommend checking out our free online course on the basics of the nRF Connect SDK: https://academy.nordicsemi.com/courses/nrf-connect-sdk-fundamentals/

Hieu

[Repa]

Greetings,

thank you for the quick response!

Ok - now the sample compiles

However when trying to build with custom configuration I get:

In file included from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/toolchain/gcc.h:98,
                 from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/toolchain.h:50,
                 from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/kernel_includes.h:23,
                 from C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/kernel.h:17,
                 from C:/Users/mattip-local/Projects/Nordic/Sandbox/hello_world_sample/src/main.c:7:
C:/Users/mattip-local/Projects/Nordic/Sandbox/hello_world_sample/src/main.c: In function 'main':
C:/Apps/NordicSemiconductor/SDKs/v2.7.0/zephyr/include/zephyr/device.h:91:41: error: '__device_dts_ord_DT_N_ALIAS_pwm_led0_P_pwms_IDX_0_PH_ORD' undeclared (first use in this function)
   91 | #define DEVICE_NAME_GET(dev_id) _CONCAT(__device_, dev_id)

The custom board .dts file has:

/dts-v1/;
#include <nordic/nrf5340_cpuapp_qkaa.dtsi>
#include "GGHHx_Dev0_0-pinctrl.dtsi"

/ {
    model = "Custom Board auto generated by nRF Connect for VS Code (CPUAPP)";
    compatible = "None,custom-board-name-cpuapp";

    chosen {
        zephyr,console = &uart0;
        zephyr,shell-uart = &uart0;
        zephyr,uart-mcumgr = &uart0;
        zephyr,bt-mon-uart = &uart0;
        zephyr,bt-c2h-uart = &uart0;
        zephyr,sram = &sram0_image;
        zephyr,flash = &flash0;
        zephyr,code-partition = &slot0_partition;
        zephyr,sram-secure-partition = &sram0_s;
        zephyr,sram-non-secure-partition = &sram0_ns;
    };


    leds {
        compatible = "gpio-leds";
        led0: led_0 {
            gpios = <&gpio0 6 GPIO_ACTIVE_LOW>;
            label = "Green LED 0";
        };
    };

    pwmleds {
        compatible = "pwm-leds";
        pwm_led0: pwm_led_0 {
            pwms = <&sw_pwm 0 PWM_MSEC(20) PWM_POLARITY_INVERTED>;
        };
    };

};



&gpiote {
    status = "okay";
};

&gpio0 {
    status = "okay";
};

&gpio1 {
    status = "okay";
};


&pwm0 {
    status = "disabled";
};

&sw_pwm {
    status = "okay";
    channel-gpios = <&gpio0 6 PWM_POLARITY_INVERTED>;
};

What am I missing here?

[Repa]

When comparing with the sample there seems to be an alias definition missing in the devicetree_generated.h header:

Sample has:

/* Existence and alternate IDs: */
#define DT_N_S_pwmleds_S_pwm_led_0_EXISTS 1
#define DT_N_ALIAS_pwm_led0     DT_N_S_pwmleds_S_pwm_led_0
#define DT_N_NODELABEL_pwm_led0 DT_N_S_pwmleds_S_pwm_led_0

Whereas my the header generated from my code has:

/* Existence and alternate IDs: */
#define DT_N_S_pwmleds_S_pwm_led_0_EXISTS 1
#define DT_N_NODELABEL_pwm_led0 DT_N_S_pwmleds_S_pwm_led_0

Now just need to figure out how this alias is supposed to be generated...

[Repa]

And of course that is in the alias definition:

pwm-led0 = &pwm_led0;

There must be a good reason why the build system converts the dash "-" to an underscore "_" during the build process. I really do hope there is a good reason for this.