User manual

ZEUS user manual
Issue E
46
Touchscreen controller
The ZEUS supports 4-wire and 5-wire analogue resistive touchscreens using the
controller available within the Wolfson WM9712L audio CODEC. The touchscreen
controller supports the following functions:
• X co-ordinate measurement.
• Y co-ordinate measurement.
• Pen down detection with programmable sensitivity.
• Touch pressure measurement (4-wire touchscreen only).
The touchscreen can be used as a wake-up source for PXA270 from sleep mode.
The touchscreen interface is broken out on the header J1. For details see J1 –
Touchscreen connector
, page 69.
USB
There are two USB host interfaces on the ZEUS. These comply with the Universal Serial
Bus Specification Rev. 1.1, supporting data transfer at full-speed (12Mbit/s) and low-
speed (1.5Mbit/s).
There are four signal lines associated with each USB channel: VBUS, DATA+, DATA-,
GND. The USB host ports are connected to a dual USB connector, type A (J8).
A USB power control switch controls the power and protects against short-circuit
conditions. If the USB voltage is short-circuited, or more than 500mA is drawn from either
supply, the switch turns the power supply off and automatically protects the device and
board. The VBUS power supply is derived from the ZEUS +5V supply. To switch the
VBUS1 and VBUS2 power on, use the PXA270 GPIO89 and GPIO22 respectively (set
them to logic ‘1’).
USB port 2 can be configured as a client port internally within the PXA270 USB
controller, and is connected to 5-pin header J10.
For details of connector pinouts, see the sections J8 – USB connector
, page 73, and J10
– USB client header
, page 74.
More information about the USB bus and the availability of particular USB peripherals
can be found at www.usb.org
.
Host port 2 on J8 and client port on J10 can only be used one at a time. DO NOT
connect both devices at the same time.