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--- packet:ninotnc [2026/02/08 14:34] – [GPIO] m0lte
+++ packet:ninotnc [2026/02/08 14:36] (current) – [Firmware] m0lte
@@ Line 325: / Line 325: @@
 * Note - for a startup script you should always use the temporary value rather than writing to memory each time
-=== MCP2221A ===
-The MCP2221A USB chip has four GPIOs which can be used to control the mode, instead of the DIP switches. This can be useful particularly on a remote site, and removes the need for a second cable (and works with a machine without its own GPIO interface).
-This is experimental and is likely to change. See https://github.com/g5dsg/2221aTool for up to date info. Thanks to Dan for working on this.
-General steps:
-''git clone https://github.com/g5dsg/2221aTool.git''
-Install python3.
-then, once (persistent):
-''sudo python3 ./2221aTool.py setup-gpio''
-this will configure the GPIO pins as outputs, and make them all low at power on.
-then, when required (non-persistent):
-''sudo python3 ./2221aTool.py set-gpio 1111''
-where 1111 is the state of the four switches, left to right.
-Wiring as follows. **NOTE - you MUST either remove the DIP switch or leave all four switches set permanently off with the jumpers in place.**
-Note: bit of an edge case, but it is required to run ''sudo python3 ./2221aTool.py setup-gpio'' at least once on a TNC before it can be flashed with new firmware, or indeed just used normally at all, at least while some of the MODE DIP switches are set to zero.
-{{:packet:ninotnc-mcp2221a-mode.jpg?400|}}
 ===== Pinout =====
-Note: this is the BACK / SOLDER side of the PLUG.
+Note: this is the BACK / SOLDER side of the PLUG. You are looking at the solder cups, NOT the pins.
 {{:kantronicstncwiring.png|}}
@@ Line 390: / Line 361: @@
 </code>
-Use v3 firmware unless you know you have a 512kb chip, which is none of the OARC UK kits (i.e. ignore the v4 firmware - it's the same, but for the bigger chip).
+Use v3 firmware if you have a 256kb chip, or the v4 firmware if you have a 512kb chip. They are functionally identical, just tailored for the memory map of the device.
 If you get dire warnings about bricked TNCs, know is this highly unlikely. Unplug TNC, reboot system, plug TNC, try again.