'''
Extension handles usage of Trackball Breakout by Pimoroni
Product page: https://shop.pimoroni.com/products/trackball-breakout
'''
from micropython import const
import math
import struct
from kmk.keys import make_key
from kmk.kmktime import PeriodicTimer
from kmk.modules import Module
from kmk.modules.mouse_keys import PointingDevice
I2C_ADDRESS = 0x0A
I2C_ADDRESS_ALTERNATIVE = 0x0B
CHIP_ID = 0xBA11
VERSION = 1
REG_LED_RED = 0x00
REG_LED_GRN = 0x01
REG_LED_BLU = 0x02
REG_LED_WHT = 0x03
REG_LEFT = 0x04
REG_RIGHT = 0x05
REG_UP = 0x06
REG_DOWN = 0x07
REG_SWITCH = 0x08
MSK_SWITCH_STATE = 0b10000000
REG_USER_FLASH = 0xD0
REG_FLASH_PAGE = 0xF0
REG_INT = 0xF9
MSK_INT_TRIGGERED = 0b00000001
MSK_INT_OUT_EN = 0b00000010
REG_CHIP_ID_L = 0xFA
RED_CHIP_ID_H = 0xFB
REG_VERSION = 0xFC
REG_I2C_ADDR = 0xFD
REG_CTRL = 0xFE
MSK_CTRL_SLEEP = 0b00000001
MSK_CTRL_RESET = 0b00000010
MSK_CTRL_FREAD = 0b00000100
MSK_CTRL_FWRITE = 0b00001000
ANGLE_OFFSET = 0
class TrackballMode:
'''Behaviour mode of trackball: mouse movement or vertical scroll'''
MOUSE_MODE = const(0)
SCROLL_MODE = const(1)
class Trackball(Module):
'''Module handles usage of Trackball Breakout by Pimoroni'''
def __init__(self, i2c, mode=TrackballMode.MOUSE_MODE, address=I2C_ADDRESS):
self._i2c_address = address
self._i2c_bus = i2c
self.pointing_device = PointingDevice()
self.mode = mode
self.previous_state = False # click state
self.polling_interval = 20
chip_id = struct.unpack('<H', bytearray(self._i2c_rdwr([REG_CHIP_ID_L], 2)))[0]
if chip_id != CHIP_ID:
raise RuntimeError(
'Invalid chip ID: 0x{:04X}, expected 0x{:04X}'.format(chip_id, CHIP_ID)
)
make_key(
names=('TB_MODE',),
on_press=self._tb_mode_press,
on_release=self._tb_mode_press,
)
def during_bootup(self, keyboard):
self._timer = PeriodicTimer(self.polling_interval)
def before_matrix_scan(self, keyboard):
'''
Return value will be injected as an extra matrix update
'''
if not self._timer.tick():
return
up, down, left, right, switch, state = self._read_raw_state()
if self.mode == TrackballMode.MOUSE_MODE:
x_axis, y_axis = self._calculate_movement(right - left, down - up)
if x_axis >= 0:
self.pointing_device.report_x[0] = x_axis
else:
self.pointing_device.report_x[0] = 0xFF & x_axis
if y_axis >= 0:
self.pointing_device.report_y[0] = y_axis
else:
self.pointing_device.report_y[0] = 0xFF & y_axis
self.pointing_device.hid_pending = x_axis != 0 or y_axis != 0
else: # SCROLL_MODE
if up >= 0:
self.pointing_device.report_w[0] = up
if down > 0:
self.pointing_device.report_w[0] = 0xFF & (0 - down)
self.pointing_device.hid_pending = up != 0 or down != 0
if switch == 1: # Button pressed
self.pointing_device.button_status[0] |= self.pointing_device.MB_LMB
self.pointing_device.hid_pending = True
if not state and self.previous_state is True: # Button released
self.pointing_device.button_status[0] &= ~self.pointing_device.MB_LMB
self.pointing_device.hid_pending = True
self.previous_state = state
return
def after_matrix_scan(self, keyboard):
return
def before_hid_send(self, keyboard):
return
def after_hid_send(self, keyboard):
if self.pointing_device.hid_pending:
keyboard._hid_helper.hid_send(self.pointing_device._evt)
self._clear_pending_hid()
return
def on_powersave_enable(self, keyboard):
return
def on_powersave_disable(self, keyboard):
return
def set_rgbw(self, r, g, b, w):
'''Set all LED brightness as RGBW.'''
self._i2c_rdwr([REG_LED_RED, r, g, b, w])
def set_red(self, value):
'''Set brightness of trackball red LED.'''
self._i2c_rdwr([REG_LED_RED, value & 0xFF])
def set_green(self, value):
'''Set brightness of trackball green LED.'''
self._i2c_rdwr([REG_LED_GRN, value & 0xFF])
def set_blue(self, value):
'''Set brightness of trackball blue LED.'''
self._i2c_rdwr([REG_LED_BLU, value & 0xFF])
def set_white(self, value):
'''Set brightness of trackball white LED.'''
self._i2c_rdwr([REG_LED_WHT, value & 0xFF])
def _clear_pending_hid(self):
self.pointing_device.hid_pending = False
self.pointing_device.report_x[0] = 0
self.pointing_device.report_y[0] = 0
self.pointing_device.report_w[0] = 0
self.pointing_device.button_status[0] = 0
def _read_raw_state(self):
'''Read up, down, left, right and switch data from trackball.'''
left, right, up, down, switch = self._i2c_rdwr([REG_LEFT], 5)
switch, switch_state = (
switch & ~MSK_SWITCH_STATE,
(switch & MSK_SWITCH_STATE) > 0,
)
return up, down, left, right, switch, switch_state
def _calculate_movement(self, raw_x, raw_y):
'''Calculate accelerated movement vector from raw data'''
if raw_x == 0 and raw_y == 0:
return 0, 0
var_accel = 1
power = 2.5
angle_rad = math.atan2(raw_y, raw_x) + ANGLE_OFFSET
vector_length = math.sqrt(pow(raw_x, 2) + pow(raw_y, 2))
vector_length = pow(vector_length * var_accel, power)
x = math.floor(vector_length * math.cos(angle_rad))
y = math.floor(vector_length * math.sin(angle_rad))
limit = 127 # hid size limit
x_clamped = max(min(limit, x), -limit)
y_clamped = max(min(limit, y), -limit)
return x_clamped, y_clamped
def _i2c_rdwr(self, data, length=0):
'''Write and optionally read I2C data.'''
while not self._i2c_bus.try_lock():
pass
try:
if length > 0:
result = bytearray(length)
self._i2c_bus.writeto_then_readfrom(
self._i2c_address, bytes(data), result
)
return list(result)
else:
self._i2c_bus.writeto(self._i2c_address, bytes(data))
return []
finally:
self._i2c_bus.unlock()
def _tb_mode_press(self, key, keyboard, *args, **kwargs):
self.mode = not self.mode