This is a combined ROM and RAM card designed to work with the RC2014 bus.

It features

• Enhanced RC2014 bus
• Selectable memory* options 8K, 16K or 32K
• Board can be used as RAM only or ROM only or both.
• Options for nMRD/nMWR or nRD/nWR signals
• Option for 27C512 with Hi/Lo ROM (A15) select
• IC Decoder 74xx138 using A15/A14/A13 (with extra options for A13 & A14)
• 8 or 16-bit wide data bus**

Notes: Both ROM and RAM memories must be the same size. * see explanation below

It will work with either the standard RC2014 bus or the latest enhanced bus where all the Z80 CPU signals are available.

Please note, this is an experimenters board. There is no fancy memory paging etc., its simple memory architecture was designed to be flexible and allow the user to experiment with other CPU architectures on the RC2014 bus. It was originally designed to work with our 8052 CPU.

The option for either nMRD and nMWR (nRD and nWR or'ed with nMREQ) signals or nRD and nWR only signals when IC3 (74xx32) is fitted or not fitted allows for experimenting with other CPU Read/Write architectures.

RAM and ROM memory space positions are movable. For example ROM can be located at top or bottom of the memory space.

The enhanced RC2014 bus features a 16-bit data bus. The card can use this enhancement by allowing the selection of the high or low 8-bit portion of 16-bit data bus. This allows the user to experiment with 16-bit CPUs such as 68000 or 8086 when two cards are used together.

For more information on origins of RC2014 see:

https://rc2014.co.uk/

and join the RC2014 forum at:

https://groups.google.com/forum/#!forum/rc2014-z80

Notes:

• This is for PCB only

• This product is made in accordance with the "designed for RC2014" labelling scheme.

• The RC2014 name is a trademark of RFC2795 Ltd.