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PIC interface for AT keyboard
21. August 2008 - 21:17 — admin
Three PIC circuits for PS/AT keyboard interfacing plus one more PIC keyboard solution.
AT Keyboard Interface V1.04 - AT keyboard interface with RS232 link using PIC16F84.
AT keyboard to RS232 interface for the personal computer or RS232 compatible devices. This routine converts AT keyboard scan patterns to ASCII characters and sends them afterwards to the target device by using the RS232 transmission protocol. Support of english (QWERTY) and modified swiss-german (QWERTZ) 'codepages'.
AT Keyboard Interface V2.04 - RS232 terminal with LCD display using PIC16F84.
AT keyboard to RS232 interface for the personal computer or RS232 compatible devices. This routine converts AT keyboard scan patterns to ASCII characters and transmits them afterwards to the target device by using the RS232 transmission protocol. Support of english (QWERTY) and modified swiss-german (QWERTZ) 'codepages'. This implementation features a LCD display as visual interface, but only for transmitted characters typed on the local keyboard (unidirectional data flow). RS232 data transmission is carried out using a software routine. No reception of characters sent from RS232 target device, because no RS232 modules with preemptive data reception available yet.
AT Keyboard Interface V3.05 - Fully operating RS232 terminal with LCD display using PIC 16C74A
The same as above, but reception of external serial data is done using an interrupt-based acquisition scheme. Visualization of received data on the first line, user-entered data on the second line of the dot matrix LCD display.
AT Keyboard Box V2.05 - Fully operating RS232 terminal with LCD display and numeric foil-keypad using PIC16F77. Multiple input devices are attached, such as an AT keyboard and a small numeric foil-keypad. The application features a dot matrix LCD display to visualize the data received from the RS232 client on the first line, and the characters typed on the locally attached keyboard on the second line. There is also a piezo-beeper for acoustic feedback. This program converts AT keyboard scan patterns to ASCII characters and transmits them afterwards to the target device by using the RS232 transmission protocol. RS232 communication is carried out by the microcontroller-internal USART, i.e. completely hardware-based RS232 data transmission and reception.