IBM 6580 User Manual

The data is transmitted from the key-
board logic card through the keyboard
cable to the system electronics in
serial form. The transmission and
line control of data from the keyboard
to the system electronics is con-
trolled by the Data Clock, the Data
Strobe, the Keyboard Acknowledge, and
the Serial Data line (Figure 5-8).
Figure 5-8. Keyboard
Transfer
Serial Data
•
•
The Data Clock synchronizes the
keyboard and the system electron-
ics allowing data to be transmit-
ted.
One byte of data (8 data bits: 0,
1, 2, 3, 4, 5, 6, 7) is transmit-
ted through the Data line.
• A Data Strobe bit is transmitted
following the data byte to signal
the system electronics that one
byte of data has been transmitted.
• The Keyboard Acknowledge signal is
transmitted by the system elec-
tronics and acknowledges receipt
of the data. It inhibits the
transmission of the next byte of
data in the buffer until the pres-
ent byte has been stored by the
system electronics.
The data is converted to an eight bit
data byte by the keyboard adapter in
the system electronics. The data
byte contains a seven bit code indi-
cating the key position. The eighth
bit in the data byte indicates a key
depression and key release for
make/break keys or repeat mode for
typamatic keys.
The keyboard data flow is shown in
Figure 5-9.
Chapter 5. Keyboard 5-7

IBM 6580 Specifications

General

Brand	IBM
Model	6580
Category	Desktop
Language	English