Subfunctions 00H—04H are available on the PCjr but are not supported by the PC or PC/XT ROM BIOS. Subfunction 05H is available on PC/ATs with ROM BIOS's dated 11/15/85 and later, and on the PS/2.Sets the ROM BIOS key repeat ("typematic") rate and delay.
Call with:
On the PC/AT and PS/2
AH = 03H
AL = 05H
BH = repeat delay (see Notes)
BL = repeat rate (see Notes)
On the PCjr
AH = 03H
AL = subfunction
00H to restore default rate and delay
01H to increase initial delay
02H to decrease repeat rate by one-half
03H to increase delay and decrease repeat rate by
one-half
04H to turn off keyboard repeat
Returns:
Nothing
Notes:
Subfunctions 00H—04H are available on the PCjr but are not supported by the PC or PC/XT ROM BIOS. Subfunction 05H is available on PC/ATs with ROM BIOS's dated 11/15/85 and later, and on the PS/2.
On the PC/AT and PS/2, the value in BH controls the amount of delay before the first repeat key is generated. The delay is always a multiple of 250 milliseconds:
Value Delay (msec.) 00H 250 01H 500 02H 750 03H 1000
On the PC/AT and PS/2, the value for the repeat rate in characters per second can be chosen from the following table:
Value Repeat rate (characters per second) 00H 30.0 01H 26.7 02H 24.0 03H 21.8 04H 20.0 05H 18.5 06H 17.1 07H 16.0 08H 15.0 09H 13.3 0AH 12.0 0BH 10.9 0CH 10.0 0DH 9.2 0EH 8.6 0FH 8.0 10H 7.5 11H 6.7 12H 6.0 13H 5.5 14H 5.0 15H 4.6 16H 4.3 17H 4.0 18H 3.7 19H 3.3 1AH 3.0 1BH 2.7 1CH 2.5 1DH 2.3 1EH 2.1 1FH 2.0