rslr/amiga-bootcamp
1
0
Fork 0
mirror of https://github.com/alfishe/amiga-bootcamp.git synced 2026-06-13 00:26:28 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions
amiga-bootcamp/01_hardware/ecs_a600_a3000
History
Ilia Sharin c4522ef2ed Add memory types article, expand blitter cookbook, update cross-references 
New articles:
- 01_hardware/common/memory_types.md: comprehensive Chip/Fast/Slow RAM reference
  with DMA accessibility matrix, per-model configurations (A500-A4000),
  accelerator memory expansion (classic + modern), adaptive software behavior,
  pitfalls with impact analysis, FPGA/emulation notes
- AGENTS.md: documentation standards and methodology guidelines

Blitter programming (08_graphics/blitter_programming.md):
- Rewrote minterm truth table with narrative explanation and worked  example
- Added 7 advanced use cases with assembly/C code: shifted BOB, hardware scroll,
  area fill polygon, interleaved bitplane BOBs, double-buffered game loop,
  GUI window drag, tile map renderer
- Added Good/Bad Patterns section with 5 named antipatterns
- Added Practical Limitations table (10 constraints with workarounds)
- Expanded Common Minterms table with Description and Real-World Use Case columns

Cross-reference updates:
- Root README: added memory types to coverage, quick start, section index
- 01_hardware/README: updated common/ folder description
- address_space.md: linked to memory_types.md and chip_ram_expansion.md
- memory_management.md (exec): linked to hardware memory types reference
- bitmap.md, sprites.md, animation.md, audio.md: linked to memory_types.md
  explaining DMA Chip RAM requirement for each subsystem
- chip_ram_expansion.md: linked to comprehensive memory types article
2026-04-25 14:12:46 -04:00
..
chip_ram_expansion.md Add memory types article, expand blitter cookbook, update cross-references 2026-04-25 14:12:46 -04:00
chipset_ecs.md docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections 2026-04-23 12:17:35 -04:00
ecs_registers_delta.md docs(amiga): make cross-references clickable markdown links 2026-04-23 12:24:21 -04:00
gary_gayle.md docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections 2026-04-23 12:17:35 -04:00
productivity_modes.md docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections 2026-04-23 12:17:35 -04:00
README.md docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections 2026-04-23 12:17:35 -04:00

README.md

← Home · Hardware

ECS Chipset — A600 / A3000 / A500+

Overview

The Enhanced Chip Set (ECS) is a significant revision of OCS, shipping from 1990 onward. It adds 2 MB Chip RAM addressing, programmable display timing, and extended registers while maintaining full backward compatibility with OCS software.

Chip Summary

Chip Part Changes from OCS
Super Agnus MOS 8372A Addresses 2 MB Chip RAM, extended DMA window
ECS Denise MOS 8373 BPLCON3, border blank, programmable sync
Paula MOS 8364 Unchanged

Contents

File Topic
chipset_ecs.md Super Agnus and ECS Denise internals
ecs_registers_delta.md New/changed registers vs OCS
productivity_modes.md Multiscan/productivity display modes
gary_gayle.md Gary (A3000) and Gayle (A600) chips: IDE, PCMCIA
chip_ram_expansion.md 2 MB Chip RAM with Super Agnus

ECS vs OCS — Key Differences

Feature OCS ECS
Max Chip RAM 1 MB (Fat Agnus) 2 MB (Super Agnus)
Display sync Fixed NTSC/PAL BEAMCON0 — programmable
Bitplane scroll 4-bit (BPLCON1) Extended (ECS Denise)
Border blank No BPLCON3 border control
Hires sprites No ECS Denise extended sprite control
DMA window Smaller Extended: wider bitplane fetch

Identifying ECS at Runtime

#include <exec/execbase.h>

struct ExecBase *SysBase = *((struct ExecBase **)4);
/* AttnFlags does not directly identify chipset */

/* Use graphics.library GfxBase->ChipRevBits0 */
#include <graphics/gfxbase.h>
struct GfxBase *GfxBase = (struct GfxBase *)OpenLibrary("graphics.library", 0);
if (GfxBase->ChipRevBits0 & GFXB_BIG_BLITTER) { /* ECS+ */ }
if (GfxBase->ChipRevBits0 & GFXB_HR_AGNUS)    { /* Super Agnus */ }
if (GfxBase->ChipRevBits0 & GFXB_HR_DENISE)   { /* ECS Denise */ }

Machines Using ECS

Model Notes
A3000 Super Agnus + ECS Denise; 68030; SCSI; Zorro III
A500+ Super Agnus (1 MB variant); ECS Denise; no IDE
A600 Super Agnus (1 MB variant); ECS Denise; Gayle; IDE; PCMCIA
A2000 (late) Some late rev boards shipped with ECS chips

References

  • ADCD 2.1 Hardware Manual — ECS extension chapters
  • NDK39: graphics/gfxbase.h — ChipRevBits0 flags
  • Amiga Hardware Reference Manual 3rd ed. — ECS appendix