PIC To PS/2 Mouse and Keyboard Interfacing

摘要

Many circuits based on PIC microcontrollers use switches to set a variety of factors. Sometimes many switches are needed, in some cases requiring the use of multiplexed keypads. However, there are instances where some, if not all, of those switches may only be used rarely, except in the initial setting-up process. So far we have probably all accepted this situation as a fact of life and not considered the expense of seldom-used switches to be of any significance - it's all part of the process of getting a particular design working as we want it. Those who are familiar with PIC programming and have suitable facilities, have at their disposal the ability to actually change settings from outside the unit. For instance, there is the option to externally send data codes to the PIC's internal data EEPROM registers, from where the software can pick up the values as part of its general processing.