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-rw-r--r--decoders/nes_gamepad/__init__.py54
-rw-r--r--decoders/nes_gamepad/pd.py105
2 files changed, 159 insertions, 0 deletions
diff --git a/decoders/nes_gamepad/__init__.py b/decoders/nes_gamepad/__init__.py
new file mode 100644
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+++ b/decoders/nes_gamepad/__init__.py
@@ -0,0 +1,54 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2019 Stephan Thiele <stephan.thiele@mailbox.org>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+'''
+This decoder stacks on top of the 'spi' PD and decodes the button states
+of an NES gamepad.
+
+The SPI decoder needs to be configured as follows:
+
+Clock polarity = 1
+Clock phase = 0
+Bit order = msb-first
+Word size = 8
+
+Chip-select is not used and must not be assigned to any channel.
+
+Hardware setup is as follows:
+ ___
+ GND |o \
+ CUP |o o| VCC
+ OUT 0 |o o| D3
+ D1 |o o| D4
+ -----
+NES Gamepad Connector
+
+VCC - Power 5V
+GND - Ground
+CUP - Shift register clock (CLK)
+OUT 0 - Shift register latch (optional)
+D1 - Gamepad data (MOSI)
+D3 - Data (unused)
+D4 - Data (unused)
+
+Data pins D3 and D4 are not used by the standard gamepad but
+by special controllers like the Nintento Zapper light gun.
+'''
+
+from .pd import Decoder
diff --git a/decoders/nes_gamepad/pd.py b/decoders/nes_gamepad/pd.py
new file mode 100644
index 0000000..17c57ca
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+++ b/decoders/nes_gamepad/pd.py
@@ -0,0 +1,105 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2019 Stephan Thiele <stephan.thiele@mailbox.org>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+import sigrokdecode as srd
+
+class Decoder(srd.Decoder):
+ api_version = 3
+ id = 'nes_gamepad'
+ name = 'NES gamepad'
+ longname = 'Nintendo Entertainment System gamepad'
+ desc = 'NES gamepad button states.'
+ license = 'gplv2+'
+ inputs = ['spi']
+ outputs = []
+ tags = ['Retro computing']
+ options = (
+ # Currently only the standard controller is supported. This might be
+ # extended by special controllers like the Nintendo Zapper light gun.
+ {'id': 'variant', 'desc': 'Gamepad variant',
+ 'default': 'Standard gamepad', 'values': ('Standard gamepad',)},
+ )
+ annotations = (
+ ('button', 'Button states'),
+ ('no-press', 'No button press'),
+ ('not-connected', 'Gamepad unconnected')
+ )
+ annotation_rows = (
+ ('buttons', 'Button states', (0,)),
+ ('no-press', 'No button press', (1,)),
+ ('not-connected', 'Gamepad unconnected', (2,)),
+ )
+
+ def __init__(self):
+ self.reset()
+
+ def reset(self):
+ self.variant = None
+ self.ss_block = None
+ self.es_block = None
+
+ def start(self):
+ self.out_ann = self.register(srd.OUTPUT_ANN)
+ self.variant = self.options['variant']
+
+ def putx(self, data):
+ self.put(self.ss_block, self.es_block, self.out_ann, data)
+
+ def handle_data(self, value):
+ if value == 0xFF:
+ self.putx([1, ['No button is pressed']])
+ return
+
+ if value == 0x00:
+ self.putx([2, ['Gamepad is not connected']])
+ return
+
+ buttons = [
+ 'A',
+ 'B',
+ 'Select',
+ 'Start',
+ 'North',
+ 'South',
+ 'West',
+ 'East'
+ ]
+
+ bits = format(value, '08b')
+ button_str = ''
+
+ for b in enumerate(bits):
+ button_index = b[0]
+ button_is_pressed = b[1] == '0'
+
+ if button_is_pressed:
+ if button_str != '':
+ button_str += ' + '
+ button_str += buttons[button_index]
+
+ self.putx([0, ['%s' % button_str]])
+
+ def decode(self, ss, es, data):
+ ptype, mosi, miso = data
+ self.ss_block, self.es_block = ss, es
+
+ if ptype != 'DATA':
+ return
+
+ self.handle_data(miso)