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##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2015 Paul Evans <leonerd@leonerd.org.uk>
##
## 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 re
import sigrokdecode as srd
def _decode_intensity(val):
intensity = val & 0x0f
if intensity == 0:
return 'min'
elif intensity == 15:
return 'max'
else:
return intensity
registers = {
0x00: ['No-op', lambda _: ''],
0x09: ['Decode', lambda v: '0b{:08b}'.format(v)],
0x0A: ['Intensity', _decode_intensity],
0x0B: ['Scan limit', lambda v: 1 + v],
0x0C: ['Shutdown', lambda v: 'off' if v else 'on'],
0x0F: ['Display test', lambda v: 'on' if v else 'off']
}
ann_reg, ann_digit, ann_warning = range(3)
class Decoder(srd.Decoder):
api_version = 3
id = 'max7219'
name = 'MAX7219'
longname = 'Maxim MAX7219/MAX7221'
desc = '8-digit LED display driver.'
license = 'gplv2+'
inputs = ['spi']
outputs = ['max7219']
annotations = (
('register', 'Registers written to the device'),
('digit', 'Digits displayed on the device'),
('warnings', 'Human-readable warnings'),
)
annotation_rows = (
('commands', 'Commands', (ann_reg, ann_digit)),
('warnings', 'Warnings', (ann_warning,)),
)
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
self.pos = 0
self.cs_start = 0
def putreg(self, ss, es, reg, value):
self.put(ss, es, self.out_ann, [ann_reg, ['%s: %s' % (reg, value)]])
def putdigit(self, ss, es, digit, value):
self.put(ss, es, self.out_ann, [ann_digit, ['Digit %d: %02X' % (digit, value)]])
def putwarn(self, ss, es, message):
self.put(ss, es, self.out_ann, [ann_warning, [message]])
def decode(self, ss, es, data):
ptype, mosi, _ = data
if ptype == 'DATA':
if not self.cs_asserted:
return
if self.pos == 0:
self.addr = mosi
self.addr_start = ss
elif self.pos == 1:
if self.addr >= 1 and self.addr <= 8:
self.putdigit(self.addr_start, es, self.addr, mosi)
elif self.addr in registers:
name, decoder = registers[self.addr]
self.putreg(self.addr_start, es, name, decoder(mosi))
else:
self.putwarn(self.addr_start, es,
'Unknown register %02X' % (self.addr))
self.pos += 1
elif ptype == 'CS-CHANGE':
self.cs_asserted = mosi
if self.cs_asserted:
self.pos = 0
self.cs_start = ss
else:
if self.pos == 1:
# Don't warn if pos=0 so that CS# glitches don't appear
# as spurious warnings.
self.putwarn(self.cs_start, es, 'Short write')
elif self.pos > 2:
self.putwarn(self.cs_start, es, 'Overlong write')
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