Alberto
01-16-2009, 10:38 AM
The "Universal Keypad System" project is based on a PIC 16F873.
The MCU controls the 10 columns and 4 rows of a rather big matrix, to detect which key has been pressed and as e result send out, via serial TTL the corresponding ascii character.
The rightmost key of row 4 is always used by the system, as a level selector.
Since there are three usable levels then the total characters (Keys) available are 117
The Keypad is sizable from 1 column to 10 columns to fit almost all the embedded projects.
Companion in the universal keypad system is the VB application "Keypad Tool" necessary to configure or re-configure the keypad.
The main features of the keypad are:
Keypad with a max 40 keys obtained with a matrix 10 Columns x 4 Rows
Using "Keypad Tool" software, columns are sizable to any number between 1 to 10
Works with Interrupt on change technique, using DT instant interrupts routine
Works on 3 selectable levels, using one key press, giving a max of 117 characters
available for a 40 keys keypad.
Formula to obtain the number of characters available for different column size:
Chars=(Columns x Rows x 3) - 3
Every single key can be modified by the user, using the keypad tool application.
By default "select" key is always the rightmost key of row # 4
Two way serial TTL communication @ 9600,n,8,1
Wake up positive trigger (25 ms) on a dedicated pin will be generated before sending any character
Auto repeat function can be enabled or disabled via software
Keypad configuration Downloadable and uploadable via PC serial port
Special windows application tool for keypad setup, is available.
The MCU controls the 10 columns and 4 rows of a rather big matrix, to detect which key has been pressed and as e result send out, via serial TTL the corresponding ascii character.
The rightmost key of row 4 is always used by the system, as a level selector.
Since there are three usable levels then the total characters (Keys) available are 117
The Keypad is sizable from 1 column to 10 columns to fit almost all the embedded projects.
Companion in the universal keypad system is the VB application "Keypad Tool" necessary to configure or re-configure the keypad.
The main features of the keypad are:
Keypad with a max 40 keys obtained with a matrix 10 Columns x 4 Rows
Using "Keypad Tool" software, columns are sizable to any number between 1 to 10
Works with Interrupt on change technique, using DT instant interrupts routine
Works on 3 selectable levels, using one key press, giving a max of 117 characters
available for a 40 keys keypad.
Formula to obtain the number of characters available for different column size:
Chars=(Columns x Rows x 3) - 3
Every single key can be modified by the user, using the keypad tool application.
By default "select" key is always the rightmost key of row # 4
Two way serial TTL communication @ 9600,n,8,1
Wake up positive trigger (25 ms) on a dedicated pin will be generated before sending any character
Auto repeat function can be enabled or disabled via software
Keypad configuration Downloadable and uploadable via PC serial port
Special windows application tool for keypad setup, is available.