girish2k44
Newbie level 3
AT Keybord Interfacing
Hi
I am interfacing a keyboard with AT89C2051 Microcontroller
This Microcontroller works as a Encoder in between AT Keyboard and 8085 based system
the code conversion is not similar to SCAN codes to ASCII it uses different table which i
captured with the help of Logic Analyser. I am successful in sending data and show on display of 8085 LCD based Trainer but still my programmed controller is not working as the real one it is slower and sometimes print same data on single press and sometimes repeat data.
In hardware Keyboard clock is connected to P3.1 which also works as serial Transmission (TX),
Keyboard Data pin is connected to P3.0 which also works as Receive Pin for Serial Data.
So I am in confusion wheteher the Original programmed controller is collecting data using SBUF register or as a Normal port by bit shifting method as i have programmed my controller using PORT3 as normal Input port and none of the SFR register is used
I am attaching my Code and hardware schematic and one more thing when keyboard clock is completed after key press a pin 9 P3.5 send a High to low pulse as the Acknowledgement to processor that data is available on port so it enables the buffer iC to send data to processor so confusion is whether P3.5 is used as normal bit or the Timer T1 is used for sending Acknowledgement as P3.5 also works as Timer1 and Counter1 i am attaching DSO captured Images
Need Urgent Help
Hi
I am interfacing a keyboard with AT89C2051 Microcontroller
This Microcontroller works as a Encoder in between AT Keyboard and 8085 based system
the code conversion is not similar to SCAN codes to ASCII it uses different table which i
captured with the help of Logic Analyser. I am successful in sending data and show on display of 8085 LCD based Trainer but still my programmed controller is not working as the real one it is slower and sometimes print same data on single press and sometimes repeat data.
In hardware Keyboard clock is connected to P3.1 which also works as serial Transmission (TX),
Keyboard Data pin is connected to P3.0 which also works as Receive Pin for Serial Data.
So I am in confusion wheteher the Original programmed controller is collecting data using SBUF register or as a Normal port by bit shifting method as i have programmed my controller using PORT3 as normal Input port and none of the SFR register is used
I am attaching my Code and hardware schematic and one more thing when keyboard clock is completed after key press a pin 9 P3.5 send a High to low pulse as the Acknowledgement to processor that data is available on port so it enables the buffer iC to send data to processor so confusion is whether P3.5 is used as normal bit or the Timer T1 is used for sending Acknowledgement as P3.5 also works as Timer1 and Counter1 i am attaching DSO captured Images
Need Urgent Help