ANTA 64K Memory Expansion

A 64KB memory expansion by MHT Ingenieros.

A Spanish manufactured memory expansion intended for the Spanish market.

Originally the internal ROM is located in bank 2.

It expanded BASIC with various RSX commands (software in ROM) to allow access to the additional banks.

Features: peek and poke, Screen flipping, Printer buffer, random access to files.

The price was: 13.900 pts.

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Pictures

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  Unit front

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  Unit back

• 

  PCB top

• 

  PCB bottom

Technical

• Uses port &F8F8 to latch data (read/write)
• Uses memory address to define where in 64KB ram to read/write.
• NOT Dk'Tronics compatible.
• More like a ram disc

to write:

LD BC,&F8F8 ;; ram data access
LD A,&34    ;; value to write
LD DE,&4000 ;; where in extra ram to read (0-&ffff)
DI
OUT (C),A   ;; latch data for ram
LD A,(DE)   ;; perform write into ram
EI

to read:

LD BC,&F8F8
ld de,&4000
di
in a,(c) 
ld a,(de) ;; read value from extra ram
ei

each access to the I/O port must be followed by a memory read operation. ROM uses single byte reads such as LD A,(DE)

• ROM has commands:

|SCREENCOPY,<ram page>,1

copy screen at &c000 to ram page.

numbers can't be 0 or greater than or equal to 6.

PBUFF NBUFF PEEK POKE SCREENSWAP BSAVE BLOAD CSAVE CLOAD OPEN GET CLOSE PUT MKILL MCAT MRENAME FREDSK RAMDSK CC

ROM

• MHT Ingenieros ANTA 64K.3 ROM (zipped .ROM file)