ACT apricot - Page 8

CONTENTS
2-4 TIMER
CONTENTS ............................................................... 1
INTRODUCTION ......... ......................... ........ ..... ...... 1
DESCRIPTION ..... ........ ............ ............... ........ ........... 2
General ................................................................... 2
Counter 0 ................................................................ 5
Counter 1 and 2 ...................................................... 6
Baud
Rates .............................................................. 8
2-5 CRT CONTROL
CONTENTS ............................................................... 1
INTRODUCTION ..... ...... ................... .... ........... ........ 1
DESCRIPTION .... ..... ........ ............... ................... ........ 2
General ................................................................... 2
Mode Selection ....................................................... 8
CRTCDETAIL ................. , ...................................... 10
General ................................................................ 10
Register Description ........................................... 13
Initialising the CR TC ... ...... .. .. . ... ............ ....... .. ... 16
CR TC Connections ................................ ............. 17
SCREEN RAM ...... ........ .......... ............. ...... ......... ..... 19
General ................................................................ 19
Text Mode ................................. ........................... 20
Graphics Mode .................................................... 22
SYSTEM RAM UTILISATION ........... ........... ......... 23
General ................................................................ 23
Text Mode ............................................................ 24
Graphics Mode .................................................... 25
DISPLAY UNIT CONNECTOR DETAIL ............. 26
2-6 FLOPPY DISK INTERFACE
CONTENTS ............................................................... 1
INTRODUCTION ... ................... .... .......... ........... ...... 2
DESCRIPTION ......... ................... .... .......... ........... ...... 4
General ................................................................... 4
Disk Write .............................................................. 5
Disk Read ................................................................ 5
Disk Formatting ..................................................... 6
Read/write Head Positioning ................................. 8