The virtues of the AIM 65 are detailed in the previous section, and indeed it does fulfil many roles extremely well. However, in some circumstances, more features are required than are provided in the standard unit.
We offer two ranges of extensions to the AIM 65, namely the CUBIT range made by Control Universal, and the Microflex range made by Rockwell themselves. Microflex has the advantage of being made by the same manufacturer as the AIM 65, but the British-made CUBIT system of extension offers good value for money, and a wider range as a result of being compatible throughout both the CUBIT and Acorn ranges of units.
The CUBIT range is described below, in this section. Microflex has the whole of the next section to itself.
CUBIT is an interface unit which extends the AIM 65 in four ways:-
4K RAM memory extension, which can be mapped at 0, 1, 8, 9, A, B, C, or D. As an AIM 65 extension it would normally be mapped at 1, ie from hex 1000 to 1FFF. This provides a contiguous memory expansion from the 4K RAM on board the AIM 65, and makes the system ready for further memory extensions, which are usually in 8K blocks.
4K ROM/PROM extension. A socket is provided for a 4K or 2K ROM or PROM, which can be mapped at 8, 9, A, B C, D, E or F. This is particularly convenient for mounting the DOS (disk operating system) PROM, in which case it is mapped at 8, ie hex 8000 to 8FFF.
Additional VIA 6522 chip. This provides a further 20 i/o lines and two timers. It can be mapped at 9000, 9400, 9800 or 9C00.
Data Highway Connector. The AIM 65 does have an expansion connector but the configuration of the CUBIT Data Highway Connector is to the Acorn bus standard. This makes it compatible with the entire range of Acorn and Control Universal products, and also allows ribbon cable connection, which is not possible with the 44-way AIM connector.
Using the Acorn Eurocard data bus extension on the CUBIT, further memory can be added by plugging directly onto the 64-way ribbon cable. The choice of memory cards includes the following:
Acorn 8K RAM + 8K ROM card. Code 730. £87 with 8K RAM memory. Uses 2114L RAM chips. Can take two 4K ROMs. Decoded in 8K blocks. See page 3.5
Acorn 32K DRAM card. Code 680. £149. No ROM slots. Decoded in 8K blocks. Uses sixteen 16K-bit 5V-only DRAM chips type 4816. See page 3.6
CU-MEM Universal Memory Carrier. Code 535. £70 without memory devices. £104 with 16K NMOS RAM (code 536). £132 with 16K CMOS memory (code 537). Arranged in two banks of four 28 pin sockets, which can accept NMOS or CMOS RAM, ROM or PROM, in 2K 4K or 8K devices as 24 or 28 pin packages. Complete with self-charging battery back-up circuit for non-volatile RAM. See page 2.7
CUDRAM 64K Dynamic RAM Card. Code 670. £99. 4K ROM slot. Decoded in 4K blocks. See page 2.9
A 64-way ribbon cable can be plugged into the Data Highway Connector of the CUBIT. The other end can be plugged on the back of a standard Control Universal backplane, modified for AJN 65 use. See page 2.13. Note that the AIM version carries a suffix A eg. 954A is a 14 way buffered backplane modified for ATM 65 use. Racks and subracks can be found on page 2.14, and enclosures in their own section.
4. DISK EXTENSION
A disk facility is probably the greatest increase in convenience that can be achieved with any computer. loading a 4K bytes disk file takes only about a second, and disk based two-pass machine code assembly becones very straightforward and quick. All of the AIM 65 facilities remain valid with the Control Universal disk extension, but in addition, the user gains access to the range of Acorn software, including their assembler, BASIC, Word Processor, and many others.
The minimum items required to add a disk facility to an AIM 65 are as follows:
1209 Replacement PROM for AIM65 ROM Z22, which adds DOS vectors £10 1216 Disk Operating System (DOS) in EPROM at hex 8000, mounted in the ROM socket on CUBIT, with documentation and utilities disk £45 600 CUBIT 4K interface unit £70 615 CUBIT 64-way interface cable £25 765 Floppy disk controller £134 770 Floppy disk drive (approx 100 KBytes storage) £165 775 Floppy disk connection cable £15 TOTAL £464 1140 SINGLE DISK ENCASED MINIMUM SYSTEM D2 Includes parts shown above, mounted in a 245mm (8" internal capacity) caseframe with 12V 1.5A power supply. It relies on the availability of 750mA at 5V from the user's AIM power supply. One further card, eg memory, video etc, can be accomodated in the rack. £550 1141 As 1140 above, but without the provision of the CUBIT card £480 1150 SINGLE DISK BASED 19" RACK SYSTEM WITH POWER SUPPLY RD1 This is similar to the D1 system above, but has a full 19" caseframe with 16.8" internal capacity, and provided with 8 Eurosockets and associated card guides, and a disk module mounted on module guides. Of the eight sockets one is used for the floppy disk card, and the other seven are completely free for user determination. The power supply is 3A at 5V, plus 1.5A at 12V. £679 1151 As 1150 above but without CUBIT £609 1160 DOUBLE DISK DOUBLE HEIGHT 19" RACK SYSTEM WITH POWER SUPPLY RD2 This is similar to the RD1 system above but the power supply is Increased to 5A 5V plus 1.5A 12V, the lower half of the rack is provided with 14 Eurosockets and associated card guides, and the upper half is provided with two disk drives. £999 1161 As 1160, but without CUBIT £929