amiga-bootcamp/01_hardware/ecs_a600_a3000/README.md

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# 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](chipset_ecs.md) | Super Agnus and ECS Denise internals |
| [ecs_registers_delta.md](ecs_registers_delta.md) | New/changed registers vs OCS |
| [productivity_modes.md](productivity_modes.md) | Multiscan/productivity display modes |
| [gary_system_controller.md](gary_system_controller.md) | Gary — A3000 bus controller, DMA arbitration, SCSI glue |
| [Gayle IDE & PCMCIA](../common/gayle_ide_pcmcia.md) | A600 Gayle: IDE and PCMCIA (shared with A1200) |
| [chip_ram_expansion.md](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

```c
#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
docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections Comprehensive technical documentation covering: - Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives - Boot sequence: cold boot through startup-sequence - Binary format: HUNK executable spec, relocation, debug info - Linking & ABI: .fd files, LVO tables, register calling conventions - Exec kernel: tasks, interrupts, memory, signals, semaphores - AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting - Graphics: planar bitmaps, Copper programming, HAM/EHB modes - Intuition: screens, windows, IDCMP, BOOPSI - Devices: trackdisk, SCSI, serial, timer, audio, keyboard - Libraries: utility, expansion, IFFParse, locale, ARexx - Networking: bsdsocket API, SANA-II, TCP/IP stack comparison - Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging - Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies - CPU & MMU: 68040/060 emulation libs, PMMU, cache management - Driver development: SANA-II, Picasso96/RTG, AHI audio All files include breadcrumb navigation. No local paths or proprietary content. 2026-04-23 12:16:52 -04:00			`[← Home](../../README.md) · [Hardware](../README.md)`

			`# 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](chipset_ecs.md) \| Super Agnus and ECS Denise internals \|`
			`\| [ecs_registers_delta.md](ecs_registers_delta.md) \| New/changed registers vs OCS \|`
			`\| [productivity_modes.md](productivity_modes.md) \| Multiscan/productivity display modes \|`
Peripherals and models description improved and expanded 2026-04-25 14:51:45 -04:00			`\| [gary_system_controller.md](gary_system_controller.md) \| Gary — A3000 bus controller, DMA arbitration, SCSI glue \|`
			`\| [Gayle IDE & PCMCIA](../common/gayle_ide_pcmcia.md) \| A600 Gayle: IDE and PCMCIA (shared with A1200) \|`
docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections Comprehensive technical documentation covering: - Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives - Boot sequence: cold boot through startup-sequence - Binary format: HUNK executable spec, relocation, debug info - Linking & ABI: .fd files, LVO tables, register calling conventions - Exec kernel: tasks, interrupts, memory, signals, semaphores - AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting - Graphics: planar bitmaps, Copper programming, HAM/EHB modes - Intuition: screens, windows, IDCMP, BOOPSI - Devices: trackdisk, SCSI, serial, timer, audio, keyboard - Libraries: utility, expansion, IFFParse, locale, ARexx - Networking: bsdsocket API, SANA-II, TCP/IP stack comparison - Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging - Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies - CPU & MMU: 68040/060 emulation libs, PMMU, cache management - Driver development: SANA-II, Picasso96/RTG, AHI audio All files include breadcrumb navigation. No local paths or proprietary content. 2026-04-23 12:16:52 -04:00			`\| [chip_ram_expansion.md](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`

			```c
			`#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`