Quantity   Component name
1 × Atmel ATMega-644 20 Mhz 40-pin dip
1 × Hitachi H628128LP 128Kbyte SRAM 32-pin dip, 100ns or faster obsolete, but many substitions are possible,; it is a very common pinout
2 × 74HCT244 bus transceiver HCT is required for at least one of these. (HC not guaranteed for SD card level shifter)
1 × 74HCT573 octal transparent latch HC may be substituted
1 × LM7805 5v regulator LM317 may be used with minor modification. Heat sink recommended. (I used a piece of scrap metal)
1 × LM317 variable regulator 3.3 regular may be substitited with little modification. I did not have any on-hand, so I used an extra LM317. If a LDO regulator is used, the 3.3v supply can draw off the 5v supply, decreasing heat.
1 × MAX232 RS-232 level converter Many 'generic' equivalents available
1 × 1n4001 diode optional, but provides safety for reverse polarity power supply
3 × 1n914 diode optional, but clamps VGA output to ~.6 to .7v (safety)
1 × PS/2 female DIN connector
1 × 15 pin female hi density D-sub connector (VGA)
1 × 9-pin male D-sub connector RS-232 By convention, computers have male conntors with DTE pinout. This is a 'computer' so, it has the computer pinout. NULL modem cable is required for communication with a PC.
1 × Power supply DC 8V to 20V Voltage not important due to on board regulators.
1 × Perforated circuit board 4 by 6 inches Other sizes will work. Current design cut the board in half and connected together with a ribbon cable, with the intention of working on a modular system. In the end, it would have been better to have kept a single board. PC Board design is pending
1 × PS/2 Keyboard Current software has worked for every keyboard I've tested. The one pictured is a Cherry G84-4100.
1 × VGA Monitor Current software syncs well on each one I've tested. Compact 4x3 LCD monitor recommended. Widescreen is OK, if squashing/letterbox is tolerable, or software is modified to assume a 16:9 aspect ratio.
1 × SD card socket Micro SD card could also be used, if attention is paid to the pinouts. I salvaged my socket off of an old USB card reader I no longer needed.