14
Bit Definitions
Word
Bit
Function
Description
n
00 to 15
Write data bits
00 to 15
Data that will be written to the common memory from the PC by the MOV(21/030)
and read with the PC READ statement.
n+1
00
PC busy
Set by the PC program when the PC accesses common memory, and cleared
when memory access is terminated. The ASCII Unit cannot access the common
memory while this bit is set.
01
PC write
complete
Momentarily set by the PC program when the PC has completed writing data to
the common memory. When this bit goes ON, the ASCII Unit read complete flag
n+3 (01) goes ON as well.
02
PC read
complete
Momentarily set by the PC program when the PC has completed reading data
from the common memory. When this bit goes ON, the ASCII Unit write complete
flag n+3 (02) goes OFF as well.
03
Restart
The ASCII Unit is activated at the trailing edge of this flag (when the flag goes
OFF). A differentiated signal must be used for the Restart signal.
04 to 07
Interrupt number
bits 00 to 03
Serves as an interrupt number when the ON PC statement is used.When bits 00
to 03 are converted into hexadecimal 00 to 15, 00 is ignored and 01 to 15 are
used as valid interrupt numbers.
08 to 15
Output data bits
00 to 07
Data output from the PC to the ASCII Unit, written by the MOV and read with the
PC GET statement.
n+2
00 to 15
Read data bits
00 to 15
Data that will be written to the common memory from the ASCII Unit with the PC
WRITE statement and read with the MOV.
n+3
00
ASCII busy
Set when the ASCII Unit accesses the common memory and cleared when
memory access is terminated. The PC cannot access common memory while this
bit is set.
01
ASCII read
complete
Momentarily set when the PC write complete flag goes ON enabling the ASCII
Unit to read from common memory. This flag is cleared when the ASCII Unit
terminates the read operation.
02
ASCII write
complete
Set at the time the ASCII Unit terminates a write operation to the common
memory and cleared when the PC read complete flag goes ON.
03
ASCII error
Set when an ASCII Unit error occurs, when RESET is activated, or when the
ASCII Unit restarts.
04
Port 1 error
Set when a reception buffer overflows or transmission error occurs at Port 1.
Turns OFF when the CLOSE statement is executed or the program is stopped.
05
Port 2 error
Set when a reception buffer overflows or transmission error occurs at Port 2.
Turns OFF when the CLOSE statement is executed or the program is stopped.
06
Battery error
Set when the battery is low or removed.
07
BASIC RUN
Set when the BASIC program is running.
08 to 15
Input data bits
00 to 07
Data written with the PC PUT statement and read with the MOV.
Note
1. Apart from the data used to read bit 00 to 15 of word n+2, the input data of bit
08 to 15 of word n+2 can be used for program control of the PC by transmit-
ting the 8-bit data to the PC.
2. When the reset switch is turned ON, the data in word n+1 will be $FFF9. Re-
starting can be checked using bit 03 of word n+1.
When the ASCII Unit is restarted, the data of word n+1 will be 0000.
Data Configuration
Summary of Contents for C500-ASC04
Page 1: ...C500 ASC04 ASCII Unit Operation Manual Revised February 2001 ...
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