Getting the internal LED to work

Legato Application Framework
1

Hello there,

I recently (a week or two ago), attended a legato training session in Johannesburg. I’ve only recently started playing around with this board, and am having problems finding and understanding resources that are necessary for development.

I’ve been told the MangOH Red has an internal LED (onboard), and would like to simply turn it on, or off.

The CF3 example doesn’t seem to handle this, because changing the values to pin7 returns

Jan  6 00:36:17 | gpioCf3Demo[9125]/gpioCf3PinComponent T=main | Internal LED switch
Jan  6 00:36:17 | gpioCf3Demo[9125]/gpioCf3PinComponent T=main | Pin7 read active: 0
Jan  6 00:36:17 | gpioCf3Demo[9125]/gpioCf3PinComponent T=main | Pin7 read PP - High: 1
Jan  6 00:36:17 | gpioCf3Demo[9125]/gpioCf3PinComponent T=main | Pin7 read PP - High: 0
Jan  6 00:36:17 | gpioCf3Demo[9125]/gpioCf3PinComponent T=main | Pin7 read PP - Low: 1
Jan  6 00:36:17 | gpioCf3Demo[9125]/gpioCf3PinComponent T=main | Pin7 read PP - Low: 0

But alas, no light switches on or off.

Please help.

2

Hi MisterBrownRSA,

Seems the naming different, it should be GPIO34 or something (sorry I don’t have MangOH red)…

Please refer to below for demo app to play with the generic LED and button:

Hope it helps.

1 Like
3 
Jan  6 05:51:28 | supervisor[11431]/supervisor T=main | Execing 'heartbeat'
Jan  6 05:51:28 | gpioService[670]/sysfsGpio T=main | Failed to export GPIO 34. Error Operation not permitted
Jan  6 05:51:28 | gpioService[670]/sysfsGpio T=main | Unable to export GPIO gpio34 for use - stopping session
Jan  6 05:51:28 | _UNKNOWN_[11431]/framework T=main | FD Monitor object name 'heartbeat.heartbeatComponent.mangoh_led' truncated to 'heartbeat.heartbeatComponent.ma'.
Jan  6 05:51:28 | heartbeat[11431]/framework T=main | sendmsg() failed with errno 32 (Broken pipe).
Jan  6 05:51:28 | heartbeat[11431]/framework T=main | Component for mangoh_led disconnected

Afraid not.

4

Which module are you using?

5

It has the wp7702, module on the mangOH red.

6

On the WP85 and WP75, GPIO34 exists. On the WP76 and WP77 the GPIO does not and thus there is no way to actuate the user LED on the mangOH red using those modules. I don’t know enough about the history to explain how this happened.

If you’re just trying to actuate an LED to validate your Legato program, then try using GPIO21 to control the IoT card LED. That will work on the wp77