Rom Subroutines - Radio Shack TRS-80 Quick Reference Manual

Notes:
ROM Subroutines
The Extended Color BASIC ROM contains many subroutines Iha!
can be called by a machine-language program: many ofthese
can also be called by a Color BASIC program via the USA
function. Each subroutine will be described in the following
format:
NAME-Enfryaddress
Operation Performed
The subroutine NAME is for reference only. Il is nol recognized by
the Computer. Entry address is given in hexadecimal form: Vou
must use an indirectjump to this address. For specifie
information on Entry and Exit Conditions, see the Technical
Information section olyoul Extended Color BASIC manual or
Section IVoI the Colol BASIC manuaL
BLKIN
==
(A006)
Reads a black Iram Cassette
BLKOUT == (A009)
Writes a block to Cassette
CHAOUT
==
(A002)
Outputs a character ta device specified by the contents of 6F.
CSADON
==
(A004)
Starts Cassette
OSKCON == (COD4)
Read or write a disk sector.
JOYtN
==
(ADDA)
Sample Joystick pots and stores values.
POLCAT
==
(AD01)
Polis the keyboard for a character.
WATLOA
==
(A7D8)
Turns the Cassette on and writes a leader.
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