Buttons

Buttons (or switches, rotary encoder) can be used in 2 configurations:

1. GPIO LTC SMPTE generator (source=internal)

Additional to the UDP messages, the Start, Stop and Resume action can also be given with buttons on GPIO pins. The mapping is as following:
  • GPIO2 -> Start action [Button <START>]
  • GPIO3 -> Stop action  [Button <STOP>]
  • GPIO6 -> Resume action  [Button <RESUME>]
The GPIO pins are active low (connecting the other side of the button to ground). See also here.

2. MCP23017

a. Source select at startup

This requires the use of the MCP23017. When the MCP23017 (with address=0x00) is detected at startup, then the source selection by means of external input is enabled.
  1. A rotary encoder can be used for selecting the source.
  2. Two buttons <LEFT>/<RIGHT> can be used for selecting the source. Mapping on the rotary encoder behavior:
    • <LEFT>= CCW
    • <RIGHT>=CW
When the appropriate source is selected, then the <SELECT> button must be pressed.

Up to 8 led's can be used for showing the selection. The selection is also showed on all other supported displays.

b. LTC SMPTE generator (source=internal)
  1. Three buttons are used. The same as with configuration 1.
The mapping for the buttons/rotary encoder is as following:
  • GPA0 -> Rotary encoder Pin A
  • GPA1 -> Rotary encoder Pin B
  • GPA2 -> Button <SELECT>
  • GPA3 -> Button <LEFT>
  • GPA4 -> Button <RIGHT>
  • GPA5 -> Button <START>
  • GPA6 -> Button <STOP>
  • GPA7 -> Button <RESUME>
The GPA pins are active low (connecting the other side of the button to ground).

The source select led's are mapped as following:
  • GPB0 -> led0 [source=ltc]
  • GPB1 -> led1 [source=artnet]
  • GPB2 -> led2 [source=midi]
  • GPB3 -> led3 [source=tcnet]
  • GPB4 -> led4 [source=internal]
  • GPB5 -> led5 [source=rtpmidi]
  • GPB6 -> led6 - currently not used
  • GPB7 -> led7 - currently not used
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