Tandy 1400LT - IV-17. Serial Interface Details

IV-17. Serial Interface
The TANDY 1400LT is equipped with two serial interfaces.
RS232C interface
or MODEM connector interface is changed by software.
Figure 4-38 shows a block diagram of these interfaces.
RS232C/MODEM DSl4C88/
DS14C89AN
-
UART SWITCHING
RS232C
CONNECTOR
Figure 4-38. Serial Interface Block Diagram
LOGIC
IC35
UART
Serial data for the TANDY 1400LT is controlled by
UART(TC8
5 70P).
The UART (IC35) performs serial-to-parallel conversion on
data characters received from RS232C connector or Internal
Modem connector, and parallel-to-serial conversion on data
characters received from the CPU.
The CPU can read the complete status of the UART
(IC35) at any time during the functional operation.
Status information reported includes the type and condition
of the transfer operations being performed by the UART, as
well as any error conditions (parity, overrun, framing, or
break interrupt).
Figure 4-39 shows the pin layout definitions of UART.
-
BOO loo I- INT
I
BO7 07
VTA
RTS
80UT
IC35
cs 1
CSO Bm
FTS
SIN
xi
x2
10 BOAINT
li 5umwrz
Figure 4-39. Pin Layout Definitions of UART
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