We updated the IO expander white paper:

http://neo900.org/stuff/papers/iox.pdf

There were quite a number of changes, as the document's role progressed from specifying design requirements towards describing what we did in the schematics.

• document current consumption of IO expander chips
• list signal names of both block diagram and schematics (so far, it was either one or the other)
• add pull-up resistors to shared sensor interrupt lines
• change orientation of LOWER-UPPER connectors from parallel to "T"
• update/correct various signals:
  • add more signals (MIC_nPRESET, SPEAKER_EN, ECI_EN, FM_nRST, MODEM_VMIC_SENSE, CELL_DETECT_IRQ)
  • add section for power configuration/status signals
  • remove IR control signals (we now use I2C for them)
  • update Hackerbus signals
  • add SWD to NFC MCU
  • update/correct reset signals (keyboard, FM, LEDs)
  • better track names in block diagram (BATT_LID, VMIC, the various SIM switch signals)

This specific version is at
http://neo900.org/stuff/papers/iox-20161231.pdf

The source can be found at
https://neo900.org/git/misc/tree/iox

- Werner