ps2io module contains classes to provide PS/2 communication.
This module is not available in some SAMD21 builds. See the Module Support Matrix - Which Modules Are Available on Which Boards for more info.
All classes change hardware state and should be deinitialized when they
are no longer needed if the program continues after use. To do so, either
deinit() or use a context manager. See
Lifetime and ContextManagers for more info.
Ps2(data_pin: microcontroller.Pin, clock_pin: microcontroller.Pin)¶
Communicate with a PS/2 keyboard or mouse
Ps2 implements the PS/2 keyboard/mouse serial protocol, used in legacy devices. It is similar to UART but there are only two lines (Data and Clock). PS/2 devices are 5V, so bidirectional level converters must be used to connect the I/O lines to pins of 3.3V boards.
Create a Ps2 object associated with the given pins.
Read one byte from PS/2 keyboard and turn on Scroll Lock LED:
import ps2io import board kbd = ps2io.Ps2(board.D10, board.D11) while len(kbd) == 0: pass print(kbd.popleft()) print(kbd.sendcmd(0xed)) print(kbd.sendcmd(0x01))
__exit__(self) → None¶
Automatically deinitializes the hardware when exiting a context. See Lifetime and ContextManagers for more info.
popleft(self) → int¶
Removes and returns the oldest received byte. When buffer is empty, raises an IndexError exception.
sendcmd(self, byte: int) → int¶
Sends a command byte to PS/2. Returns the response byte, typically the general ack value (0xFA). Some commands return additional data which is available through
byte (int) – byte value of the command
clear_errors(self) → None¶
Returns and clears a bitmap with latest recorded communication errors.
Reception errors (arise asynchronously, as data is received):
0x01: start bit not 0
0x04: parity bit error
0x08: stop bit not 1
0x10: buffer overflow, newest data discarded
Transmission errors (can only arise in the course of sendcmd()):
0x100: clock pin didn’t go to LO in time
0x200: clock pin didn’t go to HI in time
0x400: data pin didn’t ACK
0x800: clock pin didn’t ACK
0x1000: device didn’t respond to RTS
0x2000: device didn’t send a response byte in time