| # Copyright (c) 2014 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| """Emulates keyboard scan.""" |
| |
| # standard python libs |
| import time |
| |
| |
| class KeyboardEmulator(object): |
| """Controls keyboard emulator in Whale fixture. |
| |
| Keyboard emulator provides two methods: one is to trigger all row-column |
| crossings in sequence; the other is to emulate pressing of single or |
| multiple key(s) for a specified period. |
| """ |
| |
| def __init__(self, servo): |
| """Constructor.""" |
| self._servo = servo |
| self._reset() |
| self._latch_output() |
| |
| def _latch_output(self): |
| """Outputs 16 GPIOs from the 2 shift registers.""" |
| self._servo.whale_kb_shfg_latch = 'on' |
| self._servo.whale_kb_shfg_latch = 'off' |
| |
| def _reset(self): |
| """Resets the 2 shift registers.""" |
| self._servo.whale_kb_shfg_rst = 'on' |
| self._servo.whale_kb_shfg_rst = 'off' |
| |
| def _emulate(self, word, latch_shift): |
| """Emulates row-column crossing. |
| |
| For example, if the word is 0b1000000000000000, the variation in |
| two shift registers will be: |
| Shift 1: 0b0000000000000001 |
| Shift 2: 0b0000000000000010 |
| Shift 3: 0b0000000000000100 |
| ... |
| Shift16: 0b1000000000000000 |
| |
| Args: |
| word: 16-bit value of the keyboard row-column crossing status. |
| latch_shift: True to latch for each bit shift. |
| """ |
| for i in range(15, -1, -1): |
| self._servo.whale_kb_shfg_data = 'on' if (word & (1 << i)) else 'off' |
| |
| self._servo.whale_kb_shfg_clk = 'on' |
| self._servo.whale_kb_shfg_clk = 'off' |
| |
| if latch_shift: |
| self._latch_output() |
| |
| self._latch_output() |
| |
| def SimulateKeystrokes(self): |
| """Triggers all row-column crossings in sequence.""" |
| self._emulate(1 << 15, True) |
| self._reset() |
| self._latch_output() |
| |
| def KeyPress(self, bitmask, period_secs): |
| """Emulates a key press in a specific period. |
| |
| Args: |
| bitmask: 16-bit value will be output. |
| period_secs: The bitmask will be kept for a specified period. |
| """ |
| self._emulate(bitmask, False) |
| time.sleep(period_secs) |
| self._reset() |
| self._latch_output() |
