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1 | ## | |
2 | ## This file is part of the libsigrokdecode project. | |
3 | ## | |
4 | ## Copyright (C) 2019 Mickael Bosch <mickael.bosch@linux.com> | |
5 | ## | |
6 | ## This program is free software; you can redistribute it and/or modify | |
7 | ## it under the terms of the GNU General Public License as published by | |
8 | ## the Free Software Foundation; either version 2 of the License, or | |
9 | ## (at your option) any later version. | |
10 | ## | |
11 | ## This program is distributed in the hope that it will be useful, | |
12 | ## but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | ## GNU General Public License for more details. | |
15 | ## | |
16 | ## You should have received a copy of the GNU General Public License | |
17 | ## along with this program; if not, see <http://www.gnu.org/licenses/>. | |
18 | ## | |
19 | ||
20 | import sigrokdecode as srd | |
21 | ||
22 | NUM_OUTPUT_CHANNELS = 8 | |
23 | ||
24 | # TODO: Other I²C functions: general call / reset address, device ID address. | |
25 | ||
26 | class Decoder(srd.Decoder): | |
27 | api_version = 3 | |
28 | id = 'pca9571' | |
29 | name = 'NXP PCA9571' | |
30 | longname = 'NXP Semiconductors PCA9571' | |
31 | desc = 'NXP PCA9571 8-bit I²C output expander.' | |
32 | license = 'gplv2+' | |
33 | inputs = ['i2c'] | |
34 | outputs = [] | |
35 | tags = ['Embedded/industrial', 'IC'] | |
36 | annotations = ( | |
37 | ('register', 'Register type'), | |
38 | ('value', 'Register value'), | |
39 | ('warning', 'Warning messages'), | |
40 | ) | |
41 | annotation_rows = ( | |
42 | ('regs', 'Registers', (0, 1)), | |
43 | ('warnings', 'Warnings', (2,)), | |
44 | ) | |
45 | ||
46 | def __init__(self): | |
47 | self.reset() | |
48 | ||
49 | def reset(self): | |
50 | self.state = 'IDLE' | |
51 | self.last_write = 0xFF # Chip port default state is high. | |
52 | ||
53 | def start(self): | |
54 | self.out_ann = self.register(srd.OUTPUT_ANN) | |
55 | ||
56 | def putx(self, data): | |
57 | self.put(self.ss, self.es, self.out_ann, data) | |
58 | ||
59 | def handle_io(self, b): | |
60 | if self.state == 'READ DATA': | |
61 | operation = ['Outputs read', 'R'] | |
62 | if b != self.last_write: | |
63 | self.putx([2, ['Warning: read value and last write value ' | |
64 | '(%02X) are different' % self.last_write]]) | |
65 | else: | |
66 | operation = ['Outputs set', 'W'] | |
67 | self.last_write = b | |
68 | self.putx([1, [operation[0] + ': %02X' % b, | |
69 | operation[1] + ': %02X' % b]]) | |
70 | ||
71 | def check_correct_chip(self, addr): | |
72 | if addr != 0x25: | |
73 | self.putx([2, ['Warning: I²C slave 0x%02X not a PCA9571 ' | |
74 | 'compatible chip.' % addr]]) | |
75 | return False | |
76 | return True | |
77 | ||
78 | def decode(self, ss, es, data): | |
79 | cmd, databyte = data | |
80 | self.ss, self.es = ss, es | |
81 | ||
82 | # State machine. | |
83 | if cmd in ('ACK', 'BITS'): # Discard 'ACK' and 'BITS'. | |
84 | pass | |
85 | elif cmd in ('START', 'START REPEAT'): # Start a communication. | |
86 | self.state = 'GET SLAVE ADDR' | |
87 | elif cmd in ('NACK', 'STOP'): # Reset the state machine. | |
88 | self.state = 'IDLE' | |
89 | elif cmd in ('ADDRESS READ', 'ADDRESS WRITE'): | |
90 | if ((self.state == 'GET SLAVE ADDR') and | |
91 | self.check_correct_chip(databyte)): | |
92 | if cmd == 'ADDRESS READ': | |
93 | self.state = 'READ DATA' | |
94 | else: | |
95 | self.state = 'WRITE DATA' | |
96 | else: | |
97 | self.state = 'IDLE' | |
98 | elif cmd in ('DATA READ', 'DATA WRITE'): | |
99 | if self.state in ('READ DATA', 'WRITE DATA'): | |
100 | self.handle_io(databyte) | |
101 | else: | |
102 | self.state = 'IDLE' |