The ACA500plus is the successor to the popular ACA500. We've taken all our customer's suggestions, added more hardware and software, and turned an already-successful product into an Amiga user's dream.
The ACA500plus features an MC68EC000 processor, 8MBytes RAM, 8MBytes Flash, two CF card slots, an Action Replay-compatible freezer and a stylish 7-segment display called "DisMo". Several expansion ports let you add even more functionality. If you already have a memory expansion inside your A500, you can continue to use that in most cases.
This page needs lots of work. Please bear with us - the product is brand new, and not all documentation is available yet.
Software updates can be found on this page: ACA500plus_Firmware
If you are a programmer, or just interested in how the ACA500plus works internally, you can find lots of information here: ACA500plus_registers
Main Menu usage instructions
In the main menu, you can boot a previously saved profile instantaneously using the keys 1-6 of the main keyboard (not the numeric keypad!).
F1 - Boot ACA500plus complete Kickstart ROM 3.1 configuration
This will boot with a well-rounded configuration for getting a 3.1 system up and running with as much memory as possible and ACA500plus extras (IDE update, aca.resource) enabled. If an A1200 accelerator card is installed, it will be used. The 68000 CPU speed is set to 14MHz. Please note: This configuration stays in place (and overrides the previous configuration) until the next power-cycle.
F2 - Boot ACA500plus complete Kickstart ROM 1.3 configuration
This will boot with a well-rounded configuration for getting a 1.3 system up and running with as much memory as possible and ACA500plus extras (IDE update, aca.resource) enabled. If an A1200 accelerator card is installed, it will be used. The 68000 CPU speed is set to 14MHz. Please note: This configuration stays in place (and overrides the previous configuration) until the next power-cycle.
F3 - Standard A500 Profile Menu
Upon entering this section, the previous configuration will be overridden and replaced with a configuration optimized for A500 compatibility. An ACA1233n card's CPU must be disabled to enter this section, the 68000 CPU's speed will be set to 7MHz. Trapdoor memory will be enabled, fast memory disabled, PAL will be enforced, IDE update and aca.resource will be disabled. CPU speed, memory configuration and the disk drive layout can be adjusted on the following screen using keyboard shortcuts. When booting, cloaking will be enabled. Note: For selecting 1.0M Chip memory, you need both an ECS Agnus and a physical trapdoor memory expansion with a size of exactly 512k. Please remember that this configuration stays in place (and overrides the previous configuration) until the next power-cycle.
F4 - User ROM configuration
This is an overview of user-installed ROM images. Slots 1-8 are capable of keeping a 256k ROM (for example, 1.x ROMs). Every odd slot number (1, 3, 5, 7) can keep a 512k ROM (2.x, 3.x), and slots 1 and 5 can store a 1024k ROM (e.g. AROS 68k). User ROMs can be activated in the expert menu (see below, F10). For installing a user ROM, the aca.resource must be enabled, which gives access to a resident shell command, acaflashrom.
F7 - Boot ACA500plus WB 3.1 installer configuration
This will activate the 3.1 preset configuration (see F1) and boot with mounted OS 3.1 install disks: Install3.1, WB3.1, Storage3.1, Extras3.1, Locale, Fonts. The previous configuration will be overridden and this configuration stays in place until the next power-cycle. Please remember to have a CF card inserted in the boot card slot. After booting, open the Install3.1 disk icon. The easiest way to setup a new system on a fresh CF card is to use a card not larger than 4GB:
- Open HDTools, HDToolBox, click Change Drive Type, Edit Old..., Read Configuration, Save Changes to Drive and Exit.
- if that gives you problems, you can try deleting all partitions on the card, and create one amiga partition on it using eg gparted on linux. then continue with next step
- Open the HDSetup drawer, start the installer for your language, proceed with "Partition Hard Drive", enter hard drive number 0, and proceed with partitioning.
- Open the Install drawer, start the installer for your language, proceed with "Install Release 3.1".
The Aux slot is disabled by default in this mode. This is a safety precaution, as some customers have tried to install the OS on a FAT-formatted card. That's a truly bad idea, as it bears a few incompatibilities that are hard to identify as a user error. The Amiga OS should only be installed on a native Amiga file system. If you need to use the Aux slot for having a 64-bit filesystem or other patches available during install time, please launch the installer by pressing Shift-F7.
F8 - Global Profile Settings and Flash Updater
These settings are global or override their counterparts in the current configuration.
- DF0: override allows you to pretend no disk was inserted in disk drive 0, or to turn an external disk drive 1 into disk drive 0.
- DisMo brightness: Changes brightness of the dual 7-segment display on the ACA500plus.
- Max CPU speed: Limits the 68000 CPU speed globally. A maximum of 14MHz is considered safe and guaranteed, and is therefore the default setting. Note: Changing this option also affects the current configuration, it resets the CPU speed to 7MHz and limits the maximum that can be adjusted in configuration panels.
- Boot menu: Allows to boot into a saved profile automatically on a power-up, without entering the ACA500plus menu initially. Note: You can enter the ACA500plus menu again by pressing and holding the left mouse button during a reset.
- Boot menu (A1200): As above, but with an A1200 accelerator installed.
- Menu powerup mode: Allows to switch to PAL or NTSC, overriding the corresponding setting in a profile.
- Reset mode: This is a compatibility setting. You may need to set it to Sync if your system does not work reliably on a soft-reset.
- Serial logging: The ACA500plus can output debug information on the serial port of the A500 computer. If you want to see this, activate this menu item, and make a nullmodem connection to another computer using 115200 Baud/8N1 settings. Deactivate all handshaking.
- Backgroud stars: This is a global setting for the background stars in the menu system. by default, every profile has the Background stars item set to Global, meaning all profiles will use the common setting that you have chosen in this global menu.
- RTC: This is a global setting for the location of the real time clock. Normally, there is only one RTC in a system, and it makes most sense to have this one set correctly in the global configuration menu. You can still override this setting in each of your profiles.
- Reset to factory defaults: This will erase all saved profiles. Use this if you have trouble with previously-saved profiles. Note that the menu system uses US keyboard layout: German (and possibly more European) keyboard layouts have the Y key in a different position. Press the key between T and U if you really mean "yes". The last step is to press DEL, then all profiles will be erased.
Press the F key to enter the Flash ROM update procedure and follow the instructions given on the screen.
F10 - Expert options
- Force PAL/NTSC: Allows to override the display's vertical refresh rate
- Map ROM: With no accelerator card, this must be enabled to use a ROM different from the one installed on the A500 mainboard. When you disable this option and you select a different ROM, Map ROM is enabled implicitely. There is hardly any reason to switch off MapROM. In case you want to switch it off anyway, please be aware that some functions may not work as expected, such as switching off trapdoor memory.
- $C0/Trapdoor RAM: Enables or disables the A500's trapdoor memory expansion, also known as "slow mem" or "fake fastmem", as it combines the disadvantages of chip and fast memory. Many old Amiga 500 titles expect this specific kind of memory expansion, as it was affordable and thus very popular. The ACA500plus allows to enable or disable this kind of memory regardless whether there is actually trapdoor memory installed in the Amiga 500. The "Maximum" setting allows you to combine your physical 512k Trapdoor memory expansion and the 512k emulated trapdoor memory to one 1MB-block, in case a special program requires this size of memory in this specific spot. Note that this setting is incompatible with the 1M Chipram expansion (see further down).
- 7M Fast RAM: Add 7MiB of memory which unlike trapdoor memory is actually "fast" in the sense that it doesn't slow down on customchip usage.
- 1M Chip RAM expansion: This option allows to double the memory that is available for customchip access. This requires a physical trapdoor memory expansion of exactly 512k as well as an ECS Agnus, so it is not available on early OCS Amiga 500s. This option is also not available on computers with a larger trapdoor memory expansion (1.8MBytes was a popular size). We recommend to remove such 1.8M memory expansions and replace them with a plain 512k version.
- IDE driver update: This allows to use CF cards on the ACA500plus with optimal performance, and even with old kickstart versions.
- AUX CF slot: Enables the second, auxiliary CF card slot.
- VBR move: Moves the interrupt/exception vector base from lower chipmem into fast memory. This function is available on the ACA500plus, although moving the VBR is not a property of the 68ec000. Normally, this requires at least an 68010 CPU, but special circuitry of the ACA500plus makes it available to the 68ec000 processor as well. Please note that in most (if not all) cases, you also need to switch on "aca.resource" for this option to be useful, for example with the popular WHDload program.
- CPU switch: If you have an A1200 accelerator card that can switch off it's CPU (ACA1233n, B1230IV, B1240, B1260), you can use this menu item to downgrade the computer to the 68ec000 processor of the ACA500plus. If selected, the 68000-only options (such as Action Replay Freezer and CPU speed settings) can be changed. The actual CPU switch is only executed when launching the profile. The CPU setting becomes part of a saved profile.
- RTC: Realtime clock: By default, the Global setting is used (see above). Use the realtime clock on the trapdoor memory expansion, on the ACA500plus, or on the accelerator card. You can also disable it altogether. Auto-detection may not work under all circumstances. You should verify the result and may have to experiment a bit.
- CPU speed: Speed of the 68000 CPU. This value is limited by the respective setting in the global configuration (F8, above). 14MHz (the default) is considered safe and guaranteed. 21MHz and higher speeds are considered a bonus and are therefore not part of product support.
- aca.resource: The ACA resource is an "anchor" in the operating system that provides access to ACA500plus support functions: Besides some support for WHDload, it adds a resident shell command "acaflashrom" to the system.
- Virtual autoconfig: When enabled, this function adds ACA500plus support to the operating system using the standard autoconfig mechanisms, instead of patching the operating system, which is rude and more prone to incompatibilities. Recommended.
- Kickstart ROM: Choose from mainboard ROM, user ROM, or 1.2, 1.3, and 3.1 ROMs.
- Freezer: Enable the Action Replay freezer MK II or III. Please note that Action Replay can only handle the 68000 CPU. For a 680x0 monitor, use HRTMon.
- Button press: These settings allow to assign actions to short, medium and long button presses: Reset, reset to menu, pause CPU, switch CPU speeds, freeze with Action Replay, enter HRTMon, switch between PAL and NTSC.
- Background stars: By default, the Global setting is used (see above). Select a different setting for scroll direction, stop, or disable background stars altogether. The obvious use of this function is to make different configuration profiles visually distinguishable.
- Virtual Disk: Allows to insert a OS3.1 install, or a bootable or non-bootable Workbench disk.
- HRTMon: Enable HRTMon, a CPU monitor that supports higher CPUs also. On NMI allows to assign it to a button press, on Exceptions additionally invokes it when the ACA500plus receives an exception, such as an illegal instruction or division by zero.
In the expert menu you can switch profiles using the Keys 1-6 on the numeric keypad.
Flashing your own Kickstart images
When launched in full configuration, the ACA500plus provides a few shell commands as resident commands (that means, they are not files on a CF card, but available in a shell anyway). One of these commands is "acaflashrom". Usage:
- acaflashrom program <slot number> <size> <rom-filename>
The rom-file must be in pure binary format, not encrypted and without any headers. Supported sizes are 256k, 512k and 1MByte. There is a total of 8 slots numbered 1-8. Each slot is 256k, so a 512k image will occupy a pair of two slots, and must start at an odd slot number. 1MByte images must start at slot numbers 1 or 5. Please note that for using a 1M Kickstart image, you need a compatible A1200 accelerator that supports 1MByte Kickstart mapping, for example the ACA1233n. The command line:
- acaflashrom program 1 256 kick.rom
will erase and program a 256k-Kickstart into slot 1.
- acaflashrom erase <slot number>
This will erase the given slot.
A list of your flashed Kickstart images will be shown in the menu system if you press F4 in the main menu.
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