Chapter 3 — Theory of Operation
68 CV30 Fixed Mount Computer Service Manual
The USB hub will output to two host interface to the D-Sub 16-pin
connector with signal as shown in the next table.
Full Function UART
The processor has a full-function UART (FFUART) that is compatible
with the communication interface of the PC. The data rate is configurable
and can range from 9600 to 115.2 Kbps.
This port is routed out the D-Sub 9-pin RS-232 connector through a RS-
232 transceiver. The transceiver is located on the I/O board and it enables
communication with an external RS-232 device. When a connected
external device is removed, the transceiver detects the change in the input
signal voltage, and automatically enters very low power mode to conserve
power. When the external device is reconnected or powered on, the change
in state is noted and the transceiver resumes operation. The RS-232
transceiver is also under software control and can be placed in a low power
state through software.
Bluetooth UART
The main processors Bluetooth UART is connected to the second RS-232
communication port. The data rate varies from 9600 to 115.2 Kbps.
Signal Description
USBH_DP1 USB data line positive for HOST 1
USBH_DM1 USB data line negative for HOST 1
USBH_DP2 USB data line positive for HOST 2
USBH_DM2 USB data line negative for HOST 2
Signal Description Direction
COM1_DCD Data Carrier Detect Input
COM1_DSR Data Set Ready Input
COM1_DTR Data Terminal Ready Output
COM1_CTS Clear to Send Input
COM1_RTS Request to Send Output
COM1_RXD Received Data Input
COM1_TXD Transmitted Data Output
Signal Description Direction
COM2_DCD Data Carrier Detect Input
COM2_DSR Data Set Ready Input
COM2_DTR Data Terminal Ready Output
COM2_CTS Clear to Send Input
COM2_RTS Request to Send Output
COM2_RXD Received Data Input
COM2_TXD Transmitted Data Output
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