4 way clockport expander for Amiga 1200

With the 4 way clockport extension (Revision F, picture 2 or Revison H, picture 1) you can equip your Amiga 1200 with 3 additional clockports. From Revison G onwards, you can even add a Fast Clockport to port 3, which enables higher speeds. Revision G also works perfectly with the A1200 Gayle adapter (see picture 4).

Port 0 is compatible with the original clockport (address $d80001), while the other ports are the same as on the Zorro-IV board (address $d84001, $d88001 and $d8c001; Fast Clockport $90001). The design of the clockport expander was chosen in such a way that, on the one hand, it does not collide with any other expansion and, on the other hand, existing clockport expansions can continue to be used under almost optimal space conditions, even in the original housing.

Fast Clockport (from Revison G)

From revision G onwards, the 4-way clockport extension has a so-called Fast Clockport (fast clockport) at port 3, which is up to 41% faster than the standard clockport. This increases the maximum data throughput in the internal performance comparison from 612 kb/s to 867 kb/s. The performance comparison was done by Amigaworld.de on an Amiga 1200 with ACA1233n turbo card (68030 with 40 MHz clock) and a RapidRoad USB extension. A 10 MB test file was copied alternately between USB, RAM and hard disk. With faster systems, even higher values can be achieved.

From Revison H: Adaptation to turbo cards with RTC (jumper must be set if RTC module is used on adapter)

Optinonal: If the Gayle adapter is occupied by other hardware, the 4-way clock port extension can also be operated with the Rom adapter (selectable above). Disadvantage: no FastClockport available.

Overview of the different clock sports equipment tested and their function at the individual ports:

Please note: It is important to ensure your Amiga 1200 has sufficient power, space and cooling to accommodate multiple clockport expansions. Your Amiga 1200 motherboard requires a 22-pin clockport header on the right hand side of the full clockport area. Most Amiga 1200s have this but some rare revisions have the header missing or installed on the left hand side. In addition, a clock port riser card is required for simultaneous operation with an Indivision MK3.