junior computer memory card - 8K of RAM and up to 16K of EPROM

8K of RAM and up to 16K of EPROM 4K 6K 8K 12K 16K 1 421 3 42 3 4 The following is a description of the options available on the RAM and EPROM printed circuit board. 1) Up to 8K of RAM may be added (or none at all). The only limitation is that an even number of 2114"s must be used. This is because each RAM con- tains one data nibble (= half a byte). Therefore, two locations situated above each other out of the RAM IC locations must both be filled. 2) The use of the different EPROM IC types is shown in the following table. Note that the columns cannot be mixed. Additional memory area can of course be added at any time. The main advan- tage is that the cost for the complete board may be spread over a period of time, which is exactly what the principle behind the Junior Computer project set out to achieve. On examining the standard address decoding of the Junior Computer, it becomes apparent that 5K of the 8K standard decoded memory space is still unused (chip select K1 ... K5). The m...