Hi Scott,

Thank you for the feedback.  I'll look into the items you point out and will update the GitHub project.

Brian

Hi Brian,

The GPIO mapping for the LEDs is confusing.  If I leave the defines as:

#define MT3620_RDB_LED1_RED    8   // AVT_MODULE_GPIO8

#define MT3620_RDB_LED1_GREEN  9   // AVT_MODULE_GPIO9

#define MT3620_RDB_LED1_BLUE   10   // AVT_MODULE_GPIO10

Then

GPIO_SetValue(MT3620_RDB_LED1_BLUE, GPIO_Value_Low);     turns on the red LED

GPIO_SetValue(MT3620_RDB_LED1_RED, GPIO_Value_Low);       turns on the green LED

However,

GPIO_SetValue(userLedRedFd,GPIO_Value_Low);       turns on the red LED

Hi Scott,

I've confirmed with the Starter Kit documentation and with my own testing that the user RGB GPIO mapping is correct 8 for Red, 9 for Green, and 10 for Blue.  In the demo application if I connect to my IoT Hub and use the device twins to update the user RGB LEDs, they work as expected.  From the device_twin.c file

{.twinKey = "userLedRed",.twinVar = &userLedRedIsOn,.twinFd = &userLedRedFd,.twinGPIO = MT3620_RDB_LED1_RED/*8*/,.twinType = TYPE_BOOL,.active_high = false},

{.twinKey = "userLedGreen",.twinVar = &userLedGreenIsOn,.twinFd = &userLedGreenFd,.twinGPIO = MT3620_RDB_LED1_GREEN/*9*/,.twinType = TYPE_BOOL,.active_high = false},

{.twinKey = "userLedBlue",.twinVar = &userLedBlueIsOn,.twinFd = &userLedBlueFd,.twinGPIO = MT3620_RDB_LED1_BLUE/*10*/,.twinType = TYPE_BOOL,.active_high = false},

I can exercise the them using the desired properties, and they are all working as expected.

Hi Brian,

GPIO_SetValue Function

int GPIO_SetValue(int gpioFd, GPIO_Value_Type value);

Parametershttps://docs.microsoft.com/en-us/azure-sphere/reference/applibs-reference/applibs-gpio/function-gpio-setvalue#parameters

• gpioFd The file descriptor for the GPIO.
• value The GPIO_Value value to set - GPIO_Value_High or GPIO_Value_Low.

Errorshttps://docs.microsoft.com/en-us/azure-sphere/reference/applibs-reference/applibs-gpio/function-gpio-setvalue#errors

If an error is encountered, returns -1 and sets errno to the error value.

• EINVAL: the value is not a GPIO_Value.
• EBADF: the gpioFd is not valid.

Any other errno may also be specified; such errors aren't deterministic and there's no guarantee that the same behavior will be retained through system updates.

Returnshttps://docs.microsoft.com/en-us/azure-sphere/reference/applibs-reference/applibs-gpio/function-gpio-setvalue#returns

0 for success, or -1 for failure, in which case errno will be set to the error value.

The problem is that I thought the value of the file descriptor "gpioFd" was the same as the gpio pin designation.

Trying to find the "true" definition was difficult from the various included files.

from avnet_mt3620_sk.h

// User LED Red channel uses GPIO8.

#define AVNET_MT3620_SK_USER_LED_RED AVNET_AESMS_PIN11_GPIO8

// User LED Green channel uses GPIO9.

#define AVNET_MT3620_SK_USER_LED_GREEN AVNET_AESMS_PIN12_GPIO9

// User LED Blue channel uses GPIO10.

#define AVNET_MT3620_SK_USER_LED_BLUE AVNET_AESMS_PIN13_GPIO10

from mt3620.h

// MT3620 GPIO 8

#define MT3620_GPIO8 (8)

// MT3620 GPIO 9

#define MT3620_GPIO9 (9)

// MT3620 GPIO 10

#define MT3620_GPIO10 (10)

from sample_hardware.h

// MT3620 SK: User LED RED Channel.

#define SAMPLE_RGBLED_RED AVNET_MT3620_SK_USER_LED_RED

// MT3620 SK: User LED GREEN Channel.

#define SAMPLE_RGBLED_GREEN AVNET_MT3620_SK_USER_LED_GREEN

// MT3620 SK: User LED BLUE Channel.

#define SAMPLE_RGBLED_BLUE AVNET_MT3620_SK_USER_LED_BLUE

from mt3620_rdb.h

// LED 1 Red channel uses GPIO8.

#define MT3620_RDB_LED1_RED MT3620_GPIO8

// LED 1 Green channel uses GPIO9

#define MT3620_RDB_LED1_GREEN MT3620_GPIO9

// LED 1 Blue channel uses GPIO10

#define MT3620_RDB_LED1_BLUE MT3620_GPIO10

The sample files are for various target hardware configurations and I didn't realize that.

If you leave the Target Hardware Definition unconfigured, the program still compiles although runs with strange results.

Scott

Hi Scott,

Thanks for capturing all this detail!

The Avnet OOB example application was created before Microsoft implemented the Target Hardware feature.  The current Microsoft GitHub example applications use the Target Hardware feature to allow users to run each sample application on all the different hardware development kits that are currently available.