Dangerous pins

[swiftgeek]

Dangerous pins connected to straight into some rail, that could be fried very easily when misconfigured:

• RS1 - Pin25 (WTF1 signal) - 0Ω link to GND!
  • It's probably better to replace it with a high value resistor before testing alt firmware
• columns, when rows are driven (or other way around). Two possibilities exist here:
  • GPIOs don't have true "1" state - "0" (GND) path is low impedance but "1" has relatively high impedance acting more like a pull-up (like older MCUs from sinowealth)
  • GPIOs have true low impedance "1" state, and separate configurable pull-up (like newer SH68F90)
• VDP/ USB D+ is connected directly to two pins

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Since SH68F88 headers mention PxPCR registers, we have a true GPIO here (like SH68F90)!

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Safe pins:

• CAPSLOCK (LED) - unknown register
• NUMLOCK (LED) - unknown register