RTE-V831-PC
USER’S MANUAL (Rev. 2.00)
16
8.6.
COMMAND REGISTER #2 PORT (4500-5000H [READ/WRITE])
This port has the following functions:
Data bus
Logical address
Register
D7
D6
D5
D4
D3
D2
D1
D0
4500-5000H
C M D # 2
(initial value)
X
X
X
X
X
0
FRES
(0)
TOVEN
(0)
TOVEN: Controls the use of the time-over function. When the length of a bus cycle reaches 512 bus
clocks, the time-over function returns READY-, and forcibly terminates the bus cycle.
TOVEN
Time-over function
0
Used
(Reset value)
1
Not used
FRES: Resets the flash ROM.
FRES
Flash ROM
0
Reset clear
(Reset value)
1
Reset
* Access to the flash ROM is enabled only in the reset clear state.
8.7.
UART/PRINTER (TL16C552A) (4500-8000H TO 4500-A00CH)
The Texas Instruments TL16C552A (dual asynchronous communications element with FIFO) LSI is
used as UART/PRINTER controller. The TL16C552A provides two UART channels and one channel of
the bidirectional printer port (PS2-compatible). It incorporates a 16-character FIFO buffer in the UART
receive circuitry.
Each register of the TL16C552A is assigned as listed below. For an explanation of the function of each
register, refer to the manual provided with the TL16C552A.
Address
Function
Read
Write
4500-8000H
RBR/DLL
THR/DLL
4500-8004H
IER/DLM
IER/DLM
4500-8008H
IIR
FCR
4500-800CH
LCR
LCR
4500-8010H
MCR
MCR
4500-8014H
LSR
LSR
4500-8018H
MSR
MSR
4500-801CH
UART-CH#1
SCR
SCR
4500-9000H
RBR/DLL
THR/DLL
4500-9004H
IER/DLM
IER/DLM
4500-9008H
IIR
FCR
4500-900CH
LCR
LCR
4500-9010H
MCR
MCR
4500-9014H
LSR
LSR
4500-9018H
MSR
MSR
4500-901CH
UART-CH#2
SCR
SCR
4500-A000H
Read-data
Write-data
4500-A004H
Read-status
-----
4500-A008H
Read-control
Write-control
4500-A00CH
PRINTER
-----
-----
TL16C552A Register Arrangement
The CLK input of the TL16C552A is connected to the 16-MHz clock.