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1 5
1
15
I
9
I
0
9
1 5
0
1 5
1 5
2
1 5
1 0
Table 7-4. Writeable Ports
Outputs 8-bit data to the CentJILl thru 07 lines of the Centronics port. Cent-DO is the
least significant bit, Cent-07 is the most significant bit. Checks Centronics status lines for:
Out of Paper
Printer Not on tine
A C K N O W L E D G E
Sets/clears the user bit according to the least significant bit of A. A least significant bit
equal to 1 sets the user bit high. A least significant bit of 0 clears the user bit.
Sets/clears the limit pass/fail bit according to the least significant bit of A. A least significant
bit equal to 1 sets the pass/fail bit high. A least significant bit of 0 clears the pass/fail bit.
Outputs B-bit data to the Cent-DO thru 07 lines of the Centronics port. Cent-DO is the
least significant bit, Cent-D7 is the most significant bit. Sets the Printer-select signal high
Outputs a byte to the serial port. The byte is output serially according to the configuration
for the serial port.
Table 7.5. Readable Ports
Reads the serial port.
Reads the 8-bit data port Cent-DO thru 07.
Reads the user bit.
Reads the limit test pass/fail bit.
Reads the 8-bit status port.
DO-Cent-acknowledge
D l - C e n t - b u s y
Automating Measurements
Controlling Peripherals
Dsscription
Dsscription
7-55
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