XO1.75 A1 A2 Changes

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Revision as of 00:48, 29 November 2010 by Wad (talk | contribs) (SD power supplies)
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These are the changes planned for the XO-1.75 A2 prototype, from the A1 prototypes.

A1 Electrical Fixes

These changes fix problems in the A1 prototypes:

Power Sequence

  • PR89 <- 10K
  • PC55 <- DNP
  • PR66 <- 10K

SOC Reset

This adds a pullup to the SOC_RESET# line, needed due to a +1.8V input on the SOC driven by a +3.3V EC.

  • Add a 10K pullup to SOC_RESET#

OFW SPI Flash

A schottky diode was provided to isolate the +1.8V SPI Flash power from the rest of the motherboard, allowing incircuit programming. The voltage drop introduced by this diode (D6) was unacceptable.

  • Remove D6 (shorting it)

USB Power

This transfers control of the USB power from the SOC to the EC.

  • TP199 to PQ26.2 (long blue wire)
  • PR60 <- DNP (near PQ26 on the bottom side of the PCB)

USB Role

This sets the default mode of the OTG USB interface to "master".

  • Short TP39 to GND (the closest end of C??, the larger of the two capacitors right next to it)

WLAN

This corrects a default pullup on the WLAN SDIO bus.

  • R251 <- DNP
  • R250 <- 10K

Camera

This cleans up the camera clock signal.

  • L20 <- 0 ohms
  • R94 <- 22 ohms

Audio

This corrects a missing pullup on the codec reset line.

  • R36 <- 10K (top side, underneath the codec)
  • switch pins on microphone plug

Fix DCON green wiring

  • GFDDAT0~6 pins on DCON need to be wired as with CL1B, with the DCON GFDDAT0 input connected to GND.

SD Power

  • Add a turn-off clamp to the SD power supplies ?
  • Give control of SD power to the EC, not the SOC.

A1 Layout Fixes

Camera Conn.

Move the camera connector back to the correct location

Debug Conn.

  • Eliminate the Marvell JTAG debug connector.
  • Replace the Quanta JTAG debug connector with one easier to mount in the field ?

WLAN LED

The WLAN LED is misplaced on the top side of the board.

  • LED5 should be placed where LED4 is currently located, and vice versa.

Serial Connectors

  • Provide proper keepouts for the serial connectors!

Planned Feature Changes

Audio Codec

  • Change to ALC5631Q
  • Wire input circuit to route internal mic. through the audio input jack.
  • Add DC input mode
  • Add Jack Sense for the headphone jack.
  • Increase the size of R179 and R173 to 0805 (minimum), and increase the value (330 ? 470 ?) as well.

Tactile Feedback

It is still unclear what motherboard level changes are needed to support this feature.

Internal Storage

  • Change the Micro SD to external SD.
  • Add a jumper to indicate whether OFW should try to boot from internal SD or eMMC.

Embedded Controller

Change to EC IO3731

Restore Gamepad

  • Modify the game buttons from 4 buttons to 8 buttons.

Battery Charger

  • Change battery charger IC as the one used in XO-1/1.5 is being EOL'd. Modify the related circuit.

Security Processor Serial Conn.

  • Add a serial connector dedicated to use by the security processor (CForth).
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