Commodore Plus 4, Service Manual

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PLUS4 PRODUCT SPECIFICATION (Continued)
FEATURES
Built-in extended BASIC 3.5 -- over 75 commands. Built-in Machine Language monitor -- over 12
commar.ds. Built-in graphics andsound commands. Screen window capability. Reset button (Warm
start). Built-in integrated productivity software.
PERIPHERALS
C1551 Fast Disk drive, C1531 Datasette, MPS 802 Dot matrix printer, MPS 803 Dot matrix printer,
DPS 1101 Daisy wheel printer, C1802 color monitor.
OTHER PERIPHERALS
C1541 Disk drive, MPS 801 Dot matrix printer, C1702 color monitor.
PLUS 4 OVERVIEW
The Plus 4 system isbased on the 7501 microprocessor, anHMOS version of the 6510. Video pro-
cessing is achieved bythe 7360 TED chip. 64K bytes of dynamic RAM areaccomplished by 8 (64K
x 1) I.C.'s. (See page ).The system program iscontained in2 (16K x 8) ROMs. The system supports
up to 128K x 8 of ROMbanked in16K sections. By software control, through the 7360, ROM can
be completely banked out and RAM banked infor atrue 64K of RAM (minus 256 bytepages), allow-
ing 60,671 bytes available for BASIC.
Keyboard and joystick scanning are accomplished by outputting the row data onthe data buswhile
addressing aparticular register inthe TED chip. This will inturn cause the TED chip to latch the column
information.
Astandard serial port supports serial bus peripherals such asthe 1541 disk drive andthe various
serial printers. Acassette port isprovided andthe expansion port supports ROM cartrdiges. TTL serial
ASCII is intended to drive anRS-232 adapter.
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