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Appendices
Appendix D
I/O Ports
D1. BHT-3000
■ Input Ports
A user program can monitor the hardware status through the input ports by using the WAIT
statement or INP function. BHT-BASIC defines each of these ports as a byte. The table
below lists the input ports and their monitoring function in the BHT.
*1
BHT-BASIC represents the bit order by the exponent of each binary digit in the byte. For
example, bit 0 means LSB; bit 7 means MSB.
*2
This status is produced by ORing the receive buffer of the optical interface and that of the
direct-connect interface. If either of these buffers has data, therefore, this bit goes ON (1).
*3
During the direct-connect interface operation, a user program can regard RD signal as CS
signal, provided that the returned value of CS should be specified by
RS/CS control
parameter in the
OPEN "COM:" statement as listed below.
If the communications device file is closed, the BHT-3000 returns the value 0.
Port No. Bit assignment
*1
Monitors the following:
00
1
2
3
4
5
6
7
Keyboard buffer
Barcode buffer
Trigger switch
Receive buffer
*2
Value of TIMEA function
Value of
TIMEB function
Value of
TIMEC function
CS (CTS) signal
*3
0: No data
0: No data
0: OFF
0: No data
0: Nonzero
0: Nonzero
0: Nonzero
0: OFF or file closed
1: Data stored
1: Data stored
1: ON
1: Data stored
1: Zero
1: Zero
1: Zero
1: ON
3 2-0 LCD contrast level
*4 *5
0 to 7 (0: Lowest, 7: Highest)
4 0 Message version
*5 *6
0: Japanese 1: English
5 0 Alphabet entry function 0: Disabled 1: Enabled
10h-18Fh 7-0 VRAM
*5 *7
0: OFF 1: ON
OPEN "COM:" state-
ment
Returned value of CS (CTS)
OPEN "COM:,,,,0"
OPEN "COM:,,,,1"
OPEN "COM:,,,,2"
OPEN "COM:,,,,3"
OPEN "COM:,,,,4"
Always 1
Always 1
1 if RD signal is High.
1 if RD signal is Low.
Depends upon the RD signal state.
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