Usb-Serial Configuration - Psion EP10 User Manual

Chapter 4: Mechanical Considerations

USB-Serial Configuration

catches which fit in these cavities and hold the peripheral securely to the unit, but are also easily released
by the user. The EP10 HDK includes drawings and schematics of the left and right latches from the Psion
snap modules, for reference in designing these catches.
When designing your peripheral consider whether the user will need full access to the keyboard, micro-
phone, hand-strap latch, or the battery compartment while the peripheral is attached, and make sure these
areas are not covered.
There are small alignment holes on either side of the docking connector designed to accommodate studs
on the peripheral. This helps align the electrical contacts on the peripheral precisely with the contacts of
the EP10 docking connector, and to keep them from shifting during use. it is highly recommended that the
design of your peripheral includes these alignment studs.
4.4.2 USB-Serial Configuration
The C8051 microprocessor chip used with the Psion USB-serial firmware is capable of reporting different
configurations to the Psion hand-held computer. The configuration is dependant on the voltages present on
some of the C8051 GPIO pins at initialization time. See the table below for configurations supported
by EP10.
P0.0
•
1
0
0 = pulled low
The assignments are as shown to avoid conflicts when plugging in a standard USB-serial adaptor into a
vehicle cradle or desktop dock. Thus you can have two serial ports on these devices and they will not con-
flict with each other.
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Psion EP10 HDK User Manual
P0.1 P0.6 P0.7
• •
1
0 1 1
0 1 1
1 = pulled high
Comments
Standard USB serial adaptor (COM5)
USB-Serial "Port 1" (COM6)
USB-Serial "Port 2" (requires additional registry keys
for support)
All other combinations reserved for Psion use.
• = high or low