XO 1.75 A1 ECOs

These are recommended engineering change orders (ECOs) to the A1 prototype of the XO-1.75 laptop.

Power Sequence

These correct some unwise component selections.

Marked PWR SEQ on tags. Done to all boards.

• 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.

Marked as SYSRESET on tags. Done to all boards.

• 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.

Marked as SPI D6 on tags. Done to all boards.

• R87 <- 0, which has the effect of shorting D6

USB Power

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

Marked as USB on tags. Done to all boards but one of Marvell's.

• TP199 to PQ26.2 (long blue wire)
• PR60 <- DNP

USB Role

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

Marked as USBID or TP39 on tags.

• TP39 to GND

WLAN

Marked as WLAN on tags

• R251 <- DNP
• R250 <- 10K