About the ClockPorter
The ClockPorter is my first attempt at developing a Zorro card for use in big-box Amigas. It is intended to have two functions - first, to provide standard A1200-style clock ports to enable big-box Amigas to make use of the myriad of clock port peripherals available. The addresses were chosen to match the Z-IV busboard addresses, which have become a defacto standard for clockports, reproducing the original port at $D80001 and three further ports at $4000 intervals.
The second function is more or less a byproduct of the logic required for the first function: to provide real-time clock functionality to the Amiga. All big-box Amigas have a real-time clock built into their motherboards, but the age of these machines means that in many cases, the rechargeable NiCd battery that keeps the clock running has failed and leaked corrosive material onto the motherboard. Sometimes this is so bad that it stops the entire machine from booting, but often the damage is confined to the clock section of the board, resulting in a computer that otherwise works but doesn't keep the time while turned off. This can often be repaired, but for some who don't have the technical ability and don't want to send their machine off for repair, this function means they can reproduce the clock functionality elsewhere in their machine.
Space is provided for a variety of chips used in Amigas, so users can transplant their existing RTC chip onto the card if it still works. The Oki and Ricoh chips from Amiga 500+, 2000, 3000 and 4000 computers are supported via DIP sockets, and the Ricoh chip from the theoretical A1200 clock can also be fitted by soldering to the provided pads. An Epson equivalent of the Oki 6242 which is still readily available can be used too.