Product specifications

Technical/Commercial Enquiries

8.9

All technical enquiries should be directed to Technical Services at Memotech.

Completed programs and commercial enquiries should be sent to:

Mr T Spencer

Software Co-ordinator

Memotech

Unit 23 Station Lane

Whitney

Oxon

Appendix A

7.1

VDP BASIC Memory Mapping

This section gives the actual start addresses of the various tables created in VRAM by

BASIC to generate video displays and sprite patterns

Text Mode (VS 5) Start Address

Pattern name table (screen) - 7K

Pattern generator table - 6K

Graphics 2 Mode (VS 4) Start Address

Pattern name table (screen) - 15K

Pattern generator table - 0 to 6143 (Decimal)

Pattern colour table - 8K to 8K+6143

Sprite attribute table - 15K+768

Sprite generator table - 14K

Appendix B

7.2

Sprite Coincidence Flag

This is held in the VDP READ ONLY REGISTER shown in diagram 1.1 below.

(Illus 15 – Sprite coincidence register)

This register can be read and its contents examined from BASIC or machine code.

In BASIC 3000 LET READRG=INP(2)

Will return contents of this location in variable READREG

In M/C CODE IN A,(2)

Will return contents of this location in A