Set Typematic Rate/Delay (Hex F3) - IBM 5170 Technical Reference

Set Typematic Rate/Delay (Hex F3)
The system issues this command, followed by a parameter, to
change the typematic rate and delay. The typematic rate and
delay parameters are determined by the value of the byte
following the command. Bits 6 and 5 serve as the delay
parameter and bits 4,3,2, 1, and 0 (the least-significant bit) are
the rate parameter. Bit 7, the most-significant bit, is always O.
The delay is equal to 1 plus the binary value of bits 6 and 5
multiplied by 250 milliseconds ±20%. The period (interval from
one typematic output to the next) is determined by the following
equation:
Period = (8
+
A) X (2B) X 0.00417 seconds, where A = binary
value of bits 2, 1, and 0 and B
=
binary value of bits 4 and 3.
The typematic rate (make code per second) is l/period. The
period is determined by the first equation above. The following
table results.
Bit Rate
Bit Rate
00000 30.0 10000
7.5
00001
26.7
10001 6.7
00010 24.0 10010 6.0
00011 21.8 10011 5.5
00100 20.0
10100 5.0
00101 18.5 10101
4.6
00110 17.1
10110 4.3
00111 16.0
10111 4.0
01000 15.0 11000 3.7
01001 13.3 11001 3.3
01010 12.0 11010
3.0
01011 10.9 11011 2.7
01100 10.0 11100 2.5
01101 9.2 11101 2.3
01110 8.6 11110 2.1
01111 8.0
11111
2.0
Typematic Rate
The keyboard responds to the Set Typematic Rate Delay
/"""\ command with an
I
ACK
I ,
stops scanning, and waits for the rate
parameter. The keyboard responds to the rate parameter with
another
I
ACK
I ,
sets the rate and delay, and continues scanning
(if the keyboard was previously enabled). If a command is
received instead of the rate parameter, the set-typematic-rate
Keyboard 4-7