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1 | /* | |
2 | * This file is part of the sigrok project. | |
3 | * | |
4 | * Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.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 3 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 | #include "protocol.h" | |
21 | #include <stdlib.h> | |
22 | #include <string.h> | |
23 | #include <math.h> | |
24 | ||
25 | /* | |
26 | * Flags passed from the DMM. | |
27 | */ | |
28 | struct brymen_flags { | |
29 | gboolean low_batt; | |
30 | gboolean decibel, duty_cycle, hertz, amp, beep, ohm, fahrenheit; | |
31 | gboolean celsius, capacitance, diode, volt, dc, ac; | |
32 | }; | |
33 | ||
34 | struct bm850_command { | |
35 | uint8_t dle; | |
36 | uint8_t stx; | |
37 | uint8_t cmd; | |
38 | uint8_t arg[2]; | |
39 | uint8_t checksum; | |
40 | uint8_t dle2; | |
41 | uint8_t etx; | |
42 | }; | |
43 | ||
44 | struct brymen_header { | |
45 | uint8_t dle; | |
46 | uint8_t stx; | |
47 | uint8_t cmd; | |
48 | uint8_t len; | |
49 | }; | |
50 | ||
51 | struct brymen_tail { | |
52 | uint8_t checksum; | |
53 | uint8_t dle; | |
54 | uint8_t etx; | |
55 | }; | |
56 | ||
57 | /* | |
58 | * We only have one command because we only support the BM-857. However, the | |
59 | * driver is easily extensible to support more models, as the protocols are very | |
60 | * similar. | |
61 | */ | |
62 | enum { | |
63 | BM_CMD_REQUEST_READING = 0x00, | |
64 | }; | |
65 | ||
66 | ||
67 | static int bm_send_command(uint8_t command, uint8_t arg1, uint8_t arg2, | |
68 | struct sr_serial_dev_inst *serial) | |
69 | { | |
70 | struct bm850_command cmdout = { | |
71 | .dle = 0x10, .stx = 0x02, | |
72 | .cmd = command, | |
73 | .arg = {arg1, arg2}, | |
74 | .checksum = arg1^arg2, .dle2 = 0x10, .etx = 0x03}; | |
75 | int written; | |
76 | ||
77 | /* TODO: How do we compute the checksum? Hardware seems to ignore it */ | |
78 | ||
79 | /* Request reading */ | |
80 | written = serial_write(serial, &cmdout, sizeof(cmdout)); | |
81 | if(written != sizeof(cmdout)) | |
82 | return SR_ERR; | |
83 | ||
84 | return SR_OK; | |
85 | } | |
86 | ||
87 | SR_PRIV int brymen_packet_request(struct sr_serial_dev_inst *serial) | |
88 | { | |
89 | return bm_send_command(BM_CMD_REQUEST_READING, 0, 0, serial); | |
90 | } | |
91 | ||
92 | SR_PRIV int brymen_packet_length(const uint8_t *buf, int *len) | |
93 | { | |
94 | struct brymen_header *hdr; | |
95 | const int brymen_max_packet_len = 22; | |
96 | int packet_len; | |
97 | const size_t buflen = *len; | |
98 | ||
99 | hdr = (void*)buf; | |
100 | ||
101 | /* Did we receive a complete header yet? */ | |
102 | if (buflen < sizeof(*hdr) ) | |
103 | return PACKET_NEED_MORE_DATA; | |
104 | ||
105 | if (hdr->dle != 0x10 || hdr->stx != 0x02) | |
106 | return PACKET_INVALID_HEADER; | |
107 | ||
108 | /* Our packet includes the header, the payload, and the tail */ | |
109 | packet_len = sizeof(*hdr) + hdr->len + sizeof(struct brymen_tail); | |
110 | ||
111 | /* In case we pick up an invalid header, limit our search */ | |
112 | if (packet_len > brymen_max_packet_len) { | |
113 | sr_spew("Header specifies an invalid payload length: %i.", | |
114 | hdr->len); | |
115 | return PACKET_INVALID_HEADER; | |
116 | } | |
117 | ||
118 | *len = packet_len; | |
119 | sr_spew("Expecting a %d-byte packet.", *len); | |
120 | return PACKET_HEADER_OK; | |
121 | } | |
122 | ||
123 | SR_PRIV gboolean brymen_packet_is_valid(const uint8_t *buf) | |
124 | { | |
125 | struct brymen_header *hdr; | |
126 | struct brymen_tail *tail; | |
127 | int i; | |
128 | uint8_t chksum = 0; | |
129 | const uint8_t *payload = buf + sizeof(struct brymen_header); | |
130 | ||
131 | hdr = (void*)buf; | |
132 | tail = (void*)(payload + hdr->len); | |
133 | ||
134 | for (i = 0; i< hdr->len; i++) | |
135 | chksum ^= payload[i]; | |
136 | ||
137 | if (tail->checksum != chksum) { | |
138 | sr_dbg("Packet has invalid checksum 0x%.2x. Expected 0x%.2x", | |
139 | chksum, tail->checksum); | |
140 | return FALSE; | |
141 | } | |
142 | ||
143 | return TRUE; | |
144 | } | |
145 | ||
146 | static int parse_value(const char *strbuf, const int len, float *floatval) | |
147 | { | |
148 | int s, d; | |
149 | char str[32]; | |
150 | ||
151 | if (strstr(strbuf, "OL")) { | |
152 | sr_dbg("Overlimit."); | |
153 | *floatval = INFINITY; | |
154 | return SR_OK; | |
155 | } | |
156 | ||
157 | memset(str, 0, sizeof(str)); | |
158 | /* Spaces may interfere with strtod parsing the exponent. Strip them */ | |
159 | for (s = 0, d = 0; s < len; s++) | |
160 | if (strbuf[s] != ' ') | |
161 | str[d++] = strbuf[s]; | |
162 | /* YES, it's that simple !*/ | |
163 | *floatval = strtod(str, NULL); | |
164 | ||
165 | return SR_OK; | |
166 | } | |
167 | static void parse_flags(const uint8_t *buf, struct brymen_flags *info) | |
168 | { | |
169 | const uint8_t * bfunc = buf + sizeof(struct brymen_header); | |
170 | ||
171 | info->low_batt = (bfunc[3] & (1 << 7)) != 0; | |
172 | ||
173 | info->decibel = (bfunc[1] & (1 << 5)) != 0; | |
174 | info->duty_cycle = (bfunc[1] & (1 << 3)) != 0; | |
175 | info->hertz = (bfunc[1] & (1 << 2)) != 0; | |
176 | info->amp = (bfunc[1] & (1 << 1)) != 0; | |
177 | info->beep = (bfunc[1] & (1 << 0)) != 0; | |
178 | ||
179 | info->ohm = (bfunc[0] & (1 << 7)) != 0; | |
180 | info->fahrenheit = (bfunc[0] & (1 << 6)) != 0; | |
181 | info->celsius = (bfunc[0] & (1 << 5)) != 0; | |
182 | info->diode = (bfunc[0] & (1 << 4)) != 0; | |
183 | info->capacitance = (bfunc[0] & (1 << 3)) != 0; | |
184 | info->volt = (bfunc[0] & (1 << 2)) != 0; | |
185 | info->dc = (bfunc[0] & (1 << 1)) != 0; | |
186 | info->ac = (bfunc[0] & (1 << 0)) != 0; | |
187 | } | |
188 | ||
189 | SR_PRIV int sr_brymen_parse(const uint8_t *buf, float *floatval, | |
190 | struct sr_datafeed_analog *analog, void *info) | |
191 | { | |
192 | struct brymen_flags flags; | |
193 | struct brymen_header *hdr = (void*) buf; | |
194 | const uint8_t *bfunc = buf + sizeof(struct brymen_header); | |
195 | int asciilen; | |
196 | ||
197 | (void)info; | |
198 | analog->mqflags = 0; | |
199 | ||
200 | /* Give some debug info about the package */ | |
201 | asciilen = hdr->len - 4; | |
202 | sr_dbg("DMM flags: %.2x %.2x %.2x %.2x", | |
203 | bfunc[3], bfunc[2], bfunc[1], bfunc[0]); | |
204 | /* Value is an ASCII string */ | |
205 | sr_dbg("DMM packet: \"%.*s\"", asciilen, bfunc + 4); | |
206 | ||
207 | parse_flags(buf, &flags); | |
208 | parse_value((const char*)(bfunc + 4), asciilen, floatval); | |
209 | ||
210 | if (flags.volt) { | |
211 | analog->mq = SR_MQ_VOLTAGE; | |
212 | analog->unit = SR_UNIT_VOLT; | |
213 | } | |
214 | if (flags.amp) { | |
215 | analog->mq = SR_MQ_CURRENT; | |
216 | analog->unit = SR_UNIT_AMPERE; | |
217 | } | |
218 | if (flags.ohm) { | |
219 | if (flags.beep) | |
220 | analog->mq = SR_MQ_CONTINUITY; | |
221 | else | |
222 | analog->mq = SR_MQ_RESISTANCE; | |
223 | analog->unit = SR_UNIT_OHM; | |
224 | } | |
225 | if (flags.hertz) { | |
226 | analog->mq = SR_MQ_FREQUENCY; | |
227 | analog->unit = SR_UNIT_HERTZ; | |
228 | } | |
229 | if (flags.duty_cycle) { | |
230 | analog->mq = SR_MQ_DUTY_CYCLE; | |
231 | analog->unit = SR_UNIT_PERCENTAGE; | |
232 | } | |
233 | if (flags.capacitance) { | |
234 | analog->mq = SR_MQ_CAPACITANCE; | |
235 | analog->unit = SR_UNIT_FARAD; | |
236 | } | |
237 | if (flags.fahrenheit) { | |
238 | analog->mq = SR_MQ_TEMPERATURE; | |
239 | analog->unit = SR_UNIT_FAHRENHEIT; | |
240 | } | |
241 | if (flags.celsius) { | |
242 | analog->mq = SR_MQ_TEMPERATURE; | |
243 | analog->unit = SR_UNIT_CELSIUS; | |
244 | } | |
245 | if (flags.capacitance) { | |
246 | analog->mq = SR_MQ_CAPACITANCE; | |
247 | analog->unit = SR_UNIT_FARAD; | |
248 | } | |
249 | /* | |
250 | * The high-end brymen models have a configurable reference impedance. | |
251 | * When the reference impedance is changed, the DMM sends one packet | |
252 | * with the value of the new reference impedance. Both decibel and ohm | |
253 | * flags are set in this case, so we must be careful to correctly | |
254 | * identify the value as ohm, not dBmW | |
255 | */ | |
256 | if (flags.decibel && !flags.ohm) { | |
257 | analog->mq = SR_MQ_POWER; | |
258 | analog->unit = SR_UNIT_DECIBEL_MW; | |
259 | /* | |
260 | * For some reason, dBm measurements are sent by the multimeter | |
261 | * with a value three orders of magnitude smaller than the | |
262 | * displayed value. | |
263 | * */ | |
264 | *floatval *= 1000; | |
265 | } | |
266 | ||
267 | if (flags.diode) | |
268 | analog->mqflags |= SR_MQFLAG_DIODE; | |
269 | /* We can have both AC+DC in a single measurement */ | |
270 | if (flags.ac) | |
271 | analog->mqflags |= SR_MQFLAG_AC; | |
272 | if (flags.dc) | |
273 | analog->mqflags |= SR_MQFLAG_DC; | |
274 | ||
275 | if (flags.low_batt) | |
276 | sr_info("Low battery!"); | |
277 | ||
278 | return SR_OK; | |
279 | } |