AR1100 Datasheet, PDF (13/58 Pages) Microchip Technology – AR1100 Resistive USB and RS-232 Touch Screen Controller

AR1100 RESISTIVE USB AND RS-232 TOUCH SCREEN CONTROLLER
4.0 COMMUNICATION
4.1 Physical
The AR1100 supports UART and USB communication
and will automatically detect the active mode between
the two. Additionally, USB mode will enumerate as one
of three ‘devices’. The default USB device type is
defined (and can be changed) by the configuration
command and is saved in nonvolatile memory. The fac-
tory default is HID-MOUSE.
1. UART/Serial
2. HID-GENERIC
3. HID-MOUSE
4. HID-DIGITIZER
4.1.1 MODE DETECT/SELECT
To support auto-detection – the firmware and hardware
resources for UART and USB are both functional at
power-up until the active mode is determined by one of
the following events.
1. USB successfully enumerates – result: USB is
active
2. Valid communication is received via UART –
result: UART is active
3. The Sleep timer has expired and USB has not
yet enumerated – result: UART is active (by
default)
Note:
Immediately after Reset, the AR1100 will
not attempt to ‘Sleep’ for at least 45
seconds to allow time for USB
enumeration – no matter the setting of the
Sleep timer parameter.
Once the active communication mode is determined,
the ‘inactive’ mode is decommissioned to minimize
power. The active communication mode will remain in
force until the AR1100 is reset.
4.1.2 UART MODE
In UART mode, the AR1100 supports a simple, 2-wire
(transmit/receive) asynchronous serial communication.
The device does not support hardware handshaking
but does employ a data protocol handshake described
in the device command section. The host should be
configured for 9600 BAUD, 8 data bits and 1 Stop bit.
 2011 Microchip Technology Inc.
DS41606B-page 13