Page MSI-P563 User Manual
A 16550 UART provides a serial port that is software compatible
withIBMPCsoftware.Thedeviceisfullyprogrammablefor5thru
8-bit characters, selectable parity and numbers of stop bits,
BAUD rates from 50 to 56K, and a selectable mode for
16-bitI/OFIFO’s. Theportisselectable as RS-232C,RS-422, or
RS-485 using option jumpers. A hardware serial interrupt is
enabled by option jumpers to select any of four interrupt-sharing
channels.
The RS-232C electrical interface is generated by a MAX211E
that provides RX, TX, and modem control signals CTS, RTS,
DSR, DTR, RI and DCD. Input connections are made via a 10-
pin connector for a standard DTE configuration using a 10-
conductor flat-cable terminated to a DE-9P type connector (omit
outer conductor of flat cable from pin 10 of J3 in the DE-9E
connector). The RS-422 or RS-485 electrical interface is
generatedbytwo75163BdevicesthatprovideRXandTX. Input
connections are made using a 10-pin connector J4.
A82C54 intervaltimerprovidesthree16-bittimersprogrammable
in six modes. Option jumpers are provided for all gates, clock
inputs and outputs of the three channels as well as the PC/104
bussignalSYSCLK(pinB20)forusetotheclockinputs. Allclock
inputs are buffered by a socketed 74HCT00 NAND gates. The
gates and buffered clock input lines are connected to 10K pull-
up resistors. External I/O connections are made via a 10-pin
connector.
The card is I/O mapped using 16-bit addressing to select the
various devices. The 24 TTL I/O lines of the 82C55A are jumper
selectable at addresses 124H-127H on 64 distinct 1K byte
boundaries. [
Note: H denotes a hexadecimal address. This
notationwillbeusedthroughoutthemanual.
]Theserialinterface
of the PC16550 is selectable at hex addresses for COM1 thru
COM4 on 64 distinct 1K byte boundaries. The three counter/
timer channels are selectable at hex addresses 120H-123H on
64distinct1Kbyteboundaries. Otheraddressescanbeprovided
by MSI if required by programming of the 22CV10A device.
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