IFEL ROM/RAM Cartridge for Acorn BBC Master

The IFEL ROM/RAM Cartridge for Acorn BBC Master is a cartridge that fits into an available cartridge slot on the Acorn BBC Master and provides 8 selectable ROM images making them available to the computer in banks of 2.

The two switches on the far left of the board are used to select the different ROM/RAM banks available having four possible combinations.

The third switch from the left marked as TWP provides a TOTAL WRITE PROTECT feature protecting any Sideways RAM banks being overwritten.

The fourth switch along is marked as PWP and provides a PARTIAL WRITE PROTECT by only write protecting the odd numbered Sideways RAM banks.

The fifth switch, marked INH, inhibits the RAM on the board from being read or written. This is useful if a ROM has become corrupt or is faulty and the Master has locked up due to the corruption or fault.

The final switch on the right hand side of the board is then used to disable or enable the ROM socket pictured below the switch. When a ROM or EPROM is fitted, it can therefore be turned on and off as required.