Sothius' Home of Ancient Microcomputers - Amiga 500 Plus (ASSY 312812 REV.8A)

Amiga 500 Plus

Amiga 500 Plus (68 KBytes)

The Amiga 500 Plus, link between A500 and A600, with its integrated drive, an additional A1011 diskdrive, a CBM 1084 monitor, CBM 1352 mouse, manuals and AmigaDOS 2.04 system disks
(picture copyright by M.A.Grundke)

Specifications

Name Amiga 500 Plus

Codename
'B52/ Rock Lobster' (A500's codename)
Rock Lobster is a song by The B52's (from their debut album, which was just called The B52's)

Made by Commodore AMIGA Inc.

Released
1991
the first A500 appeared in 1987

Serial-No. C= COMMODORE
MODEL A500PLUS
SERIAL NO. 213404
A500+ MA 0105291363642002114508

Board-Info
C=A500 +
ARTWORK 312815
PCB FAB 312814
SCHEMATIC 312813
PCB ASSY 312812
© COPYRIGHT --
1991 COMMODORE
B52/ ROCK LOBSTER
GRR/ JSP/ FISH/ NINES
RVW/ VFA/ DCA/ WILSON
AJM/ CJW/ TC/ SMK/ BCN
ITOH/ PRY/ F+F/ LOLLI
C=A500+ REV 8A
also see the board overview

CPU Motorola MC68000

Speed 7.09379 MHz (PAL)/ 7.15909 MHz (NTSC)

RAM CSG 8375 ECS 'Fat Agnus' (PAL & NTSC-capable)
1024 KBytes ChipRAM:
8 pcs. Motorola MCM514256AP80 (256Kx4)
with A501+ RAM-expansion, the A500+ can be expanded to 2MB ChipRAM onboard
expandable to 10240 KBytes (2MB Chip-, 8MB FastRAM)
the CSG 8375 is basically the same as the A3000's MOS 8372B

ROM/ Native OS C390979-01 Kickstart 2.04 (v37.175, 512 KB ROM)
for use with AmigaDOS 2.0, later AmigaDOS 2.1 (additional localization functions and libraries)
the Kickstart 2.0 also introduced a very useful feature, which was part of all later Kickstart revisions: the boot menu. Accessed by pressing both mouse buttons simultaneously at boot time, it contains functions to
enable/ disable devices (diskdrives, harddisks, PCMCIA)

choose boot device
switch off CPU caches (useful for MC68020 or higher)
switch NTSC/ PAL (to force the appropriate mode for games)
force OCS/ ECS compatibility (AA was added in Kick 3.0)

Keyboard/ Layout CBM 6570-036 keyboard-controller
96 keys/ german (QWERTZ)

Graphics CSG 8373R4PD ECS 'Denise'
'Blitter' (filling ops & memory block moves), integrated in Agnus
'Copper' (graphic coprocessor, supports CPU in graphic ops and controls the Blitter)
Pre-defined ECS screen modes:
'LowRes': 320x256 (50Hz PAL)/ 320x200 (60Hz NTSC)
'HighRes': 640x256 (50Hz PAL)/ 640x200 (60Hz NTSC)
'SuperHighRes': 1280x256 (PAL 50Hz)/ 1280x200 (NTSC 60Hz)
'Productivity': 640x480 (58Hz)
all modes can also be interlaced, doubling vertical resolution
horizontal scan rates 15.6kHz (PAL, NTSC) and 31.44kHz (Productivity)
Simultaneous colors (from a 4096-palette):
4 (2 bitplanes) in Productivity & SuperHighRes
16 (4 bitplanes) in HighRes
32 (5 bitplanes) in LowRes
64 (6 bitplanes) in LowRes ('Halfbright')
4096 in LowRes-HAM6 mode ('Hold-and-modify', 6 bit/pixel)

Text: 60x25 or 80x25 (no 'real' text-mode, it's graphics)

Sound CSG 8364R7PD 'Paula'
4 independant hardware sound channels, each including an 8 bit DAC
can be combined to 2 channels stereo
frequency- and amplitude-modulation, low-pass filter
complex sound effects can easily be programmed
Paula also has registers for floppy control

Media integrated diskdrive: 3.5" disks, 880 KBytes/ disk
external drives like A1010/ A1011 via diskdrive connector
5.25" disks, 360/1200 KBytes for PC-compatibility (A1020 drive)
external AT-Bus (IDE) or SCSI-harddisks (via expansion-port)
later: 3.5" 1.76MB Amiga-HD-drives (compatible with PC-HD 1.44MB)

Input/ Output 2x CSG 8520PD 'CIA' (Interface I/O, timers, floppy disk I/O)
CSG 5719 'Gary' (some logic functions & floppy-motor control)
Motorola MC1488 + MC1489 (RS232)
54 pin RAM expansion-slot ('trapdoor')
85 pin male edge conn. expansion-slot (on its left, for external HDs etc.)
2x 9 pin SUB-D mouse/ joystick/ paddles

25 pin 'Centronics' parallel SUB-D
25 pin SUB-D external diskdrive
25 pin 'RS232' serial SUB-D
stereo cinch-out
23 pin SUB-D RGB jack, capable of
analog RGB (= full range of 4.096 colors)
digital RGBI (= 16 color combinations only)
monchrome composite video jack
DC-in ('square'-type)

Miscellaneous
With the Amiga 500 Plus, both Kickstart 2.0 and the Enhanced Chip Set (ECS) became finally available for the 'mass-markets' - to enjoy them before, you had to buy the professional and thus more expensive Amiga 3000

The A500 Plus can be considered as the link between the 'old' Amiga 500 and the new, cost-reduced and SMD-produced Amiga 600
The machine basically is an Amiga 500 Rev. 8 with 1 MByte ChipRAM and onboard battery backed-up clock - same as an A501- and ECS-expanded A500, except for the 8375-Agnus. However, the REV.8A board was slightly modified to be able to support the CSG 8375, allowing this machine to be expanded to 2 MB ChipRAM, using the A501+ RAM expansion (codename 'cake')
The Amiga 500 Rev. 8 and the Amiga 500 Plus were sold together for a short time, because many people who just wanted to play feared that the new machine wouldn't be as compatible as the old one (which was basically right - some games didn't work with Kickstart 2.0)

AmigaDOS 2.0 (16 KBytes)

With the Amiga 500 Plus (and A600), AmigaDOS 2.0 finally became available for the entry-level markets (after having been introduced with the A3000 earlier). Benefits were more stability, full ECS-support and a new '3D-look' for the GUI. Later, there was also AmigaDOS 2.1 (still running on all 2.04/2.05-ROMs), which came with support for multiple languages/ countries. Shown here is Kickstart 2.0 (v37.175) running Workbench 2.1 (v38.36)

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Sothius' Home - Museum - AMIGA - Amiga 500 Plus - additional pictures

Name	Amiga 500 Plus
Codename	'B52/ Rock Lobster' (A500's codename) Rock Lobster is a song by The B52's (from their debut album, which was just called The B52's)
Made by	Commodore AMIGA Inc.
Released	1991 the first A500 appeared in 1987
Serial-No.	C= COMMODORE MODEL A500PLUS SERIAL NO. 213404 A500+ MA 0105291363642002114508
Board-Info	C=A500 + ARTWORK 312815 PCB FAB 312814 SCHEMATIC 312813 PCB ASSY 312812 © COPYRIGHT -- 1991 COMMODORE B52/ ROCK LOBSTER GRR/ JSP/ FISH/ NINES RVW/ VFA/ DCA/ WILSON AJM/ CJW/ TC/ SMK/ BCN ITOH/ PRY/ F+F/ LOLLI C=A500+ REV 8A also see the board overview
CPU	Motorola MC68000
Speed	7.09379 MHz (PAL)/ 7.15909 MHz (NTSC)
RAM	CSG 8375 ECS 'Fat Agnus' (PAL & NTSC-capable) 1024 KBytes ChipRAM: 8 pcs. Motorola MCM514256AP80 (256Kx4) with A501+ RAM-expansion, the A500+ can be expanded to 2MB ChipRAM onboard expandable to 10240 KBytes (2MB Chip-, 8MB FastRAM) the CSG 8375 is basically the same as the A3000's MOS 8372B
ROM/ Native OS	C390979-01 Kickstart 2.04 (v37.175, 512 KB ROM) for use with AmigaDOS 2.0, later AmigaDOS 2.1 (additional localization functions and libraries) the Kickstart 2.0 also introduced a very useful feature, which was part of all later Kickstart revisions: the boot menu. Accessed by pressing both mouse buttons simultaneously at boot time, it contains functions to enable/ disable devices (diskdrives, harddisks, PCMCIA) choose boot device switch off CPU caches (useful for MC68020 or higher) switch NTSC/ PAL (to force the appropriate mode for games) force OCS/ ECS compatibility (AA was added in Kick 3.0)
Keyboard/ Layout	CBM 6570-036 keyboard-controller 96 keys/ german (QWERTZ)
Graphics	CSG 8373R4PD ECS 'Denise' 'Blitter' (filling ops & memory block moves), integrated in Agnus 'Copper' (graphic coprocessor, supports CPU in graphic ops and controls the Blitter) Pre-defined ECS screen modes: 'LowRes': 320x256 (50Hz PAL)/ 320x200 (60Hz NTSC) 'HighRes': 640x256 (50Hz PAL)/ 640x200 (60Hz NTSC) 'SuperHighRes': 1280x256 (PAL 50Hz)/ 1280x200 (NTSC 60Hz) 'Productivity': 640x480 (58Hz) all modes can also be interlaced, doubling vertical resolution horizontal scan rates 15.6kHz (PAL, NTSC) and 31.44kHz (Productivity) Simultaneous colors (from a 4096-palette): 4 (2 bitplanes) in Productivity & SuperHighRes 16 (4 bitplanes) in HighRes 32 (5 bitplanes) in LowRes 64 (6 bitplanes) in LowRes ('Halfbright') 4096 in LowRes-HAM6 mode ('Hold-and-modify', 6 bit/pixel) Text: 60x25 or 80x25 (no 'real' text-mode, it's graphics)
Sound	CSG 8364R7PD 'Paula' 4 independant hardware sound channels, each including an 8 bit DAC can be combined to 2 channels stereo frequency- and amplitude-modulation, low-pass filter complex sound effects can easily be programmed Paula also has registers for floppy control
Media	integrated diskdrive: 3.5" disks, 880 KBytes/ disk external drives like A1010/ A1011 via diskdrive connector 5.25" disks, 360/1200 KBytes for PC-compatibility (A1020 drive) external AT-Bus (IDE) or SCSI-harddisks (via expansion-port) later: 3.5" 1.76MB Amiga-HD-drives (compatible with PC-HD 1.44MB)
Input/ Output	2x CSG 8520PD 'CIA' (Interface I/O, timers, floppy disk I/O) CSG 5719 'Gary' (some logic functions & floppy-motor control) Motorola MC1488 + MC1489 (RS232) 54 pin RAM expansion-slot ('trapdoor') 85 pin male edge conn. expansion-slot (on its left, for external HDs etc.) 2x 9 pin SUB-D mouse/ joystick/ paddles 25 pin 'Centronics' parallel SUB-D 25 pin SUB-D external diskdrive 25 pin 'RS232' serial SUB-D stereo cinch-out 23 pin SUB-D RGB jack, capable of analog RGB (= full range of 4.096 colors) digital RGBI (= 16 color combinations only) monchrome composite video jack DC-in ('square'-type)
Miscellaneous	With the Amiga 500 Plus, both Kickstart 2.0 and the Enhanced Chip Set (ECS) became finally available for the 'mass-markets' - to enjoy them before, you had to buy the professional and thus more expensive Amiga 3000 The A500 Plus can be considered as the link between the 'old' Amiga 500 and the new, cost-reduced and SMD-produced Amiga 600 The machine basically is an Amiga 500 Rev. 8 with 1 MByte ChipRAM and onboard battery backed-up clock - same as an A501- and ECS-expanded A500, except for the 8375-Agnus. However, the REV.8A board was slightly modified to be able to support the CSG 8375, allowing this machine to be expanded to 2 MB ChipRAM, using the A501+ RAM expansion (codename 'cake') The Amiga 500 Rev. 8 and the Amiga 500 Plus were sold together for a short time, because many people who just wanted to play feared that the new machine wouldn't be as compatible as the old one (which was basically right - some games didn't work with Kickstart 2.0)