Keyboard circuit

There are many chips on the market that may be used in a keyboard circuit, but many of these are fixed and do not provide all the keys required. For example, RCA's COP 1871 is an excellent device, CMOS logic and low power requirement, but it does not provide for the backspace key to be coded as hex 08. Instead, it uses the delete key, coded as hex 7F. Although it is possible to change the software to recognize the different code, this is not always easy. The aim of the design offered here is a keyboard that can produce every code but is also able to be hooked up as a standard keyboard.