PS/2 Library
The mikroBasic PRO for FT90x provides a library for communication with the common PS/2 keyboard.

- The library does not utilize interrupts for data retrieval, and requires the oscillator clock to be at least 6MHz.
- The pins to which a PS/2 keyboard is attached should be connected to the pull-up resistors.
- Although PS/2 is a two-way communication bus, this library does not provide MCU-to-keyboard communication; e.g. pressing the Caps Lock key will not turn on the Caps Lock LED.
External dependencies of PS/2 Library
The following variables must be defined in all projects using PS/2 Library: | Description : | Example : |
---|---|---|
dim PS2_Data_Input as sbit sfr external |
PS/2 Data Input line. | dim PS2_Data_Input as sbit at GPIO_PIN43_bit |
dim PS2_Clock_Input as sbit sfr external |
PS/2 Clock Input line. | dim PS2_Clock_Input as sbit at GPIO_PIN26_bit |
dim PS2_Clock_Output as sbit sfr external |
PS/2 Clock Output line. | dim PS2_Clock_Output as sbit at GPIO_PIN26_bit |
Library Routines
Ps2_Config
Prototype |
sub procedure Ps2_Config() |
---|---|
Description |
Initializes the MCU for work with the PS/2 keyboard. |
Parameters |
None. |
Returns |
Nothing. |
Requires |
External dependencies of the library from the top of the page must be defined before using this function. |
Example |
dim PS2_Data_Input as sbit at GPIO_PIN43_bit dim PS2_Clock_Input as sbit at GPIO_PIN26_bit dim PS2_Clock_Output as sbit at GPIO_PIN26_bit ... Ps2_Config() ' Init PS/2 Keyboard |
Notes |
None. |
Ps2_Key_Read
Prototype |
sub function Ps2_Key_Read(dim byref value as byte, dim byref special as byte, dim byref pressed as byte) as word |
---|---|
Description |
The function retrieves information on key pressed. |
Parameters |
|
Returns |
|
Requires |
PS/2 keyboard needs to be initialized. See Ps2_Config routine. |
Example |
dim value, special, pressed as word ... ' Press Enter to continue: do { if (Ps2_Key_Read(value, special, pressed)) then if ((value = 13) and (special = 1)) then break end if end if loop until (0=1) |
Notes |
None. |
Special Function Keys
Key | Value returned |
---|---|
F1 | 1 |
F2 | 2 |
F3 | 3 |
F4 | 4 |
F5 | 5 |
F6 | 6 |
F7 | 7 |
F8 | 8 |
F9 | 9 |
F10 | 10 |
F11 | 11 |
F12 | 12 |
Enter | 13 |
Page Up | 14 |
Page Down | 15 |
Backspace | 16 |
Insert | 17 |
Delete | 18 |
Windows | 19 |
Ctrl | 20 |
Shift | 21 |
Alt | 22 |
Print Screen | 23 |
Pause | 24 |
Caps Lock | 25 |
End | 26 |
Home | 27 |
Scroll Lock | 28 |
Num Lock | 29 |
Left Arrow | 30 |
Right Arrow | 31 |
Up Arrow | 32 |
Down Arrow | 33 |
Escape | 34 |
Tab | 35 |
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