Custom command in MCUMGR

[dagvegar]

Hello,

My goal is to read out UICR address 0x10001080UL from command line / MCUMGR.

mcumgr --conntype serial --connstring COM8,baud=115200

How to acheive that?

I have tried and successfully compiled ran these mcumgr handler examples:

https://docs.zephyrproject.org/latest/services/device_mgmt/mcumgr_handlers.html

https://github.com/zephyrproject-rtos/zephyr/tree/main/tests/subsys/mgmt/mcumgr/handler_demo

But I don't see the new commands anywhere, not a new shell command, not a new run routine, please explain how to achieve this.

[Vidar Berg]

Hello,

You can register the mcumgr shell handler by adding CONFIG_MCUMGR_GRP_SHELL=y to your project configuration file. In addition to this configuration setting, you need to include the following configurations from the overlay-shell.conf Kconfig fragment found in the SMP server sample:

# Enable the shell MCUmgr transport.
CONFIG_BASE64=y
CONFIG_CRC=y
CONFIG_SHELL=y
CONFIG_SHELL_BACKEND_DUMMY=y
CONFIG_MCUMGR_TRANSPORT_SHELL=y

# mcumgr-cli application doesn't accepts log in the channel it uses
CONFIG_SHELL_LOG_BACKEND=n

You should then be able to register a shell command in your application. For example:

static int cmd_uicr_read(const struct shell *shell, size_t argc, char **argv)
{
	ARG_UNUSED(argc);
	ARG_UNUSED(argv);

	shell_print(shell, "UICR@0x%x: 0x%x", 
		(uint32_t) &NRF_UICR->CUSTOMER[0], NRF_UICR->CUSTOMER[0]);

	return 0;
}

SHELL_CMD_REGISTER(uicr_read, NULL, "Print UICR register", cmd_uicr_read);

Best regards,

Vidar

[dagvegar]

Thanks a lot for the answer.

The code integrates fine and flashes to my device.

Is the uicr_read command supposed to be listed here under available commands? 

 mcumgr --conntype serial --connstring COM8 shell
Execute shell commands remotely

Usage:
  mcumgr shell [flags]
  mcumgr shell [command]

Available Commands:
  exec        Execute a shell command remotely

Flags:
  -h, --help   help for shell

Global Flags:
  -c, --conn string         connection profile to use
      --connextra string    Additional key-value pair to append to the connstring
      --connstring string   Connection key-value pairs to use instead of using the profile's connstring
      --conntype string     Connection type to use instead of using the profile's type
  -i, --hci int             HCI index for the controller on Linux machine
  -l, --loglevel string     log level to use (default "info")
      --name string         name of target BLE device; overrides profile setting
      --ompres string       Use this CoAP resource instead of /omgr (default "/omgr")
  -t, --timeout float       timeout in seconds (partial seconds allowed) (default 10)
  -r, --tries int           total number of tries in case of timeout (default 1)
      --write-rsp           Send BLE acked write requests instead of unacked write commands

I don't quite see how to execute the command.

[Vidar Berg]

Please try 

mcumgr --conntype serial --connstring COM8,baud=115200 shell exec uicr_read

. I'm not sure if you can list available commands over the mcumgr transport. You can try shell exec help to see if that works.

[dagvegar]

mcumgr --conntype serial --connstring COM8,baud=115200 shell exec uicr_read
status=8

[Vidar Berg]

Please check if the CONFIG_MCUMGR_GRP_SHELL symbol got selected in your configuration file (build/zephyr/.config). The MGMT_ERR_ENOTSUP (8) error suggests that the shell handler did not get registered.

[dagvegar]

Thanks a lot, now it's working!

[dagvegar]

Though it's now working, the current consumption with the uart enabled is too high. I want to do mcumgr over USB. 

In order to disable uart:

&uart0 {
  status = "disabled";
};

It looks like

CONFIG_MCUMGR_TRANSPORT_SHELL=y

requires uart in the device tree:

ncs/v2.6.1/zephyr/include/zephyr/device.h:89:41: error: '__device_dts_ord_70' undeclared

Is it possible to keep this working over USB, but with uart disabled?

[dagvegar]

After fiddling around with different combinations, this combination works:

# Enable the serial mcumgr transport.

CONFIG_MCUMGR_TRANSPORT_UART=y

CONFIG_MCUMGR_GRP_SHELL=y

# Enable the shell MCUmgr transport.

CONFIG_BASE64=y

CONFIG_SHELL=y

CONFIG_SHELL_BACKEND_DUMMY=y

#CONFIG_MCUMGR_TRANSPORT_SHELL=y

CONFIG_SHELL_BACKEND_SERIAL=n

/ {
	chosen {
		zephyr,uart-mcumgr = &cdc_acm_uart0;
	};
};

&zephyr_udc0 {
	cdc_acm_uart0: cdc_acm_uart0 {
		compatible = "zephyr,cdc-acm-uart";
	};
};

&uart0 {
	status = "disabled";
};