What is RC2014?

RC2014 is a simple 8 bit Z80 based modular computer. It is inspired by the home built computers of the late 70s and computer revolution of the early 80s. It is not a clone of anything specific, but there are suggestions of the ZX81, UK101, S100, Superboard II and Apple I in here. It nominally has 8K ROM, 32K RAM, runs at 7.3728MHz and communicates over serial at 115,200 baud.

What is this module?

This is the clock module which is supplied with the RC2014 Pro or RC2014 Zed, although it can also be used as a replacement for the clock module supplied with the RC2014 Classic ][, or if you are building your own custom RC2014 variant. It can be used with Standard Bus backplanes (Backplane 5 or Backplane 8) with single row header pins, or with Enhanced Bus backplanes (Backplane Pro) with double row header pins. If the Standard Bus option is chosen, then a 10 pin straight header is also supplied in case you need access to the /CLK2 signals.

This is a multipurpose clock module. Primarily it generates a 7.3728Mhz clock signal to run the RC2014. This is available on pin 21 of the Standard Bus which is used to run the CPU and UART. Optionally, this signal can be duplicated on the Clock2 pin of the Enhanced Bus, which can be used to clock a second UART port.

As a multi speed clock there are several options for clock speed output. The 7.3728Mhz clock can be divided by 2, 3, 6, 8, 12 or 24, which will give outputs of 3.6864, 2.4576, 1.2288, 0.9216, 0.6144 or 0.3072Mhz respectively. Due to the serial baud rate being derived from the clock speed, this will equate to a baud rate of 57600, 38400, 19200, 14400, 9600 or 4800. Any of these speeds can be available on the primary Clock pin or the Clock2 pin.

In addition, there is a slow clock signal, of around 600Khz which, again, can be on the either the primary Clock pin or Clock2 or both.

There is an input from an external clock too. This can be derived from a signal generator, or from a basic clock module (no longer available) piggybacked on this module. Again, this signal can be on the either the primary Clock pin or Clock2 or both.

The last clock option is for a SPDT switch (not supplied) to be used to manually clock the RC2014.

The reset circuit has been upgraded to allow for an automatic reset to be triggered shortly after power is applied to the RC2014. Either the active low reset or the active high reset signal can be connected to the Reset2 pin on the enhanced bus - although be aware that this pin is also used by the Pageable ROM and 64k RAM for the page signal, so you can only have one or the other.

What do I get?

• PCB Only Just the bare PCB
• Dual Clock Single Speed PCB, single row header IC & socket, crystal, caps, resistors and reset button. Everything you need for a 7.3728Mhz clock module
• Dual Clock Multi Speed PCB, single or double row header, 5 ICs & sockets, crystal, caps, resistors, reset button, header pins and jumpers. Everything you need for multi speed output clock module

RC2014 is a trademark of RFC2795 Ltd.