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Document if or why sometimes digits/spec_digits is 0.
[libsigrok.git] / src / hardware / uni-t-dmm / protocol.c
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79081ec8 1/*
50985c20 2 * This file is part of the libsigrok project.
79081ec8 3 *
bc653a56 4 * Copyright (C) 2012-2013 Uwe Hermann <uwe@hermann-uwe.de>
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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, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
6ec6c43b 21#include <config.h>
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22#include <string.h>
23#include <glib.h>
c1aae900 24#include <libsigrok/libsigrok.h>
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25#include "libsigrok-internal.h"
26#include "protocol.h"
27
28/*
29 * Driver for various UNI-T multimeters (and rebranded ones).
30 *
31 * Most UNI-T DMMs can be used with two (three) different PC interface cables:
32 * - The UT-D04 USB/HID cable, old version with Hoitek HE2325U chip.
33 * - The UT-D04 USB/HID cable, new version with WCH CH9325 chip.
c8852687 34 * - The UT-D02 RS232 cable.
79081ec8 35 *
c8852687 36 * This driver is meant to support all USB/HID cables, and various DMMs that
79081ec8 37 * can be attached to a PC via these cables. Currently only the UT-D04 cable
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38 * (new version) is supported/tested.
39 * The UT-D02 RS232 cable is handled by the 'serial-dmm' driver.
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40 *
41 * The data for one DMM packet (e.g. 14 bytes if the respective DMM uses a
42 * Fortune Semiconductor FS9922-DMM4 chip) is spread across multiple
43 * 8-byte chunks.
44 *
45 * An 8-byte chunk looks like this:
46 * - Byte 0: 0xfz, where z is the number of actual data bytes in this chunk.
47 * - Bytes 1-7: z data bytes, the rest of the bytes should be ignored.
48 *
49 * Example:
50 * f0 00 00 00 00 00 00 00 (no data bytes)
51 * f2 55 77 00 00 00 00 00 (2 data bytes, 0x55 and 0x77)
52 * f1 d1 00 00 00 00 00 00 (1 data byte, 0xd1)
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53 */
54
f0540611 55static void decode_packet(struct sr_dev_inst *sdi, const uint8_t *buf)
79081ec8 56{
bc653a56 57 struct dev_context *devc;
f0540611 58 struct dmm_info *dmm;
79081ec8 59 struct sr_datafeed_packet packet;
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60 struct sr_datafeed_analog analog;
61 struct sr_analog_encoding encoding;
62 struct sr_analog_meaning meaning;
63 struct sr_analog_spec spec;
79081ec8 64 float floatval;
f0540611 65 void *info;
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66 int ret;
67
69e19dd7 68 devc = sdi->priv;
f0540611 69 dmm = (struct dmm_info *)sdi->driver;
869c8375 70 /* Note: digits/spec_digits will be overridden by the DMM parsers. */
dff60e3c 71 sr_analog_init(&analog, &encoding, &meaning, &spec, 0);
f0540611 72 info = g_malloc(dmm->info_size);
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73
74 /* Parse the protocol packet. */
f0540611 75 ret = dmm->packet_parse(buf, &floatval, &analog, info);
fdbcb86d 76 if (ret != SR_OK) {
bc653a56 77 sr_dbg("Invalid DMM packet, ignoring.");
f0540611 78 g_free(info);
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79 return;
80 }
81
c8852687 82 /* If this DMM needs additional handling, call the resp. function. */
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83 if (dmm->dmm_details)
84 dmm->dmm_details(&analog, info);
85
86 g_free(info);
c8852687 87
79081ec8 88 /* Send a sample packet with one analog value. */
dff60e3c 89 analog.meaning->channels = sdi->channels;
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90 analog.num_samples = 1;
91 analog.data = &floatval;
dff60e3c 92 packet.type = SR_DF_ANALOG;
79081ec8 93 packet.payload = &analog;
695dc859 94 sr_session_send(sdi, &packet);
79081ec8 95
8a63a406 96 sr_sw_limits_update_samples_read(&devc->limits, 1);
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97}
98
3ece1dff 99static int hid_chip_init(struct sr_dev_inst *sdi, uint16_t baudrate)
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100{
101 int ret;
102 uint8_t buf[5];
3ece1dff 103 struct sr_usb_dev_inst *usb;
79081ec8 104
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105 usb = sdi->conn;
106
79081ec8 107 /* Detach kernel drivers which grabbed this device (if any). */
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108 if (libusb_kernel_driver_active(usb->devhdl, 0) == 1) {
109 ret = libusb_detach_kernel_driver(usb->devhdl, 0);
79081ec8 110 if (ret < 0) {
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111 sr_err("Failed to detach kernel driver: %s.",
112 libusb_error_name(ret));
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113 return SR_ERR;
114 }
115 sr_dbg("Successfully detached kernel driver.");
116 } else {
117 sr_dbg("No need to detach a kernel driver.");
118 }
119
120 /* Claim interface 0. */
3ece1dff 121 if ((ret = libusb_claim_interface(usb->devhdl, 0)) < 0) {
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122 sr_err("Failed to claim interface 0: %s.",
123 libusb_error_name(ret));
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124 return SR_ERR;
125 }
126 sr_dbg("Successfully claimed interface 0.");
127
bc653a56 128 /* Set data for the HID feature report (e.g. baudrate). */
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129 buf[0] = baudrate & 0xff; /* Baudrate, LSB */
130 buf[1] = (baudrate >> 8) & 0xff; /* Baudrate, MSB */
131 buf[2] = 0x00; /* Unknown/unused (?) */
132 buf[3] = 0x00; /* Unknown/unused (?) */
133 buf[4] = 0x03; /* Unknown, always 0x03. */
134
135 /* Send HID feature report to setup the baudrate/chip. */
136 sr_dbg("Sending initial HID feature report.");
137 sr_spew("HID init = 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x (%d baud)",
138 buf[0], buf[1], buf[2], buf[3], buf[4], baudrate);
139 ret = libusb_control_transfer(
3ece1dff 140 usb->devhdl, /* libusb device handle */
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141 LIBUSB_REQUEST_TYPE_CLASS |
142 LIBUSB_RECIPIENT_INTERFACE |
143 LIBUSB_ENDPOINT_OUT,
144 9, /* bRequest: HID set_report */
145 0x300, /* wValue: HID feature, report number 0 */
146 0, /* wIndex: interface 0 */
147 (unsigned char *)&buf, /* payload buffer */
148 5, /* wLength: 5 bytes payload */
149 1000 /* timeout (ms) */);
150
151 if (ret < 0) {
d4928d71 152 sr_err("HID feature report error: %s.", libusb_error_name(ret));
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153 return SR_ERR;
154 }
155
156 if (ret != 5) {
157 /* TODO: Handle better by also sending the remaining bytes. */
158 sr_err("Short packet: sent %d/5 bytes.", ret);
159 return SR_ERR;
160 }
161
162 sr_dbg("Successfully sent initial HID feature report.");
163
164 return SR_OK;
165}
166
167static void log_8byte_chunk(const uint8_t *buf)
168{
169 sr_spew("8-byte chunk: %02x %02x %02x %02x %02x %02x %02x %02x "
170 "(%d data bytes)", buf[0], buf[1], buf[2], buf[3],
171 buf[4], buf[5], buf[6], buf[7], (buf[0] & 0x0f));
172}
173
174static void log_dmm_packet(const uint8_t *buf)
175{
176 sr_dbg("DMM packet: %02x %02x %02x %02x %02x %02x %02x"
177 " %02x %02x %02x %02x %02x %02x %02x",
178 buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6],
179 buf[7], buf[8], buf[9], buf[10], buf[11], buf[12], buf[13]);
180}
181
f0540611 182static int get_and_handle_data(struct sr_dev_inst *sdi)
79081ec8 183{
79081ec8 184 struct dev_context *devc;
f0540611 185 struct dmm_info *dmm;
bc653a56 186 uint8_t buf[CHUNK_SIZE], *pbuf;
79081ec8 187 int i, ret, len, num_databytes_in_chunk;
3ece1dff 188 struct sr_usb_dev_inst *usb;
79081ec8 189
79081ec8 190 devc = sdi->priv;
f0540611 191 dmm = (struct dmm_info *)sdi->driver;
3ece1dff 192 usb = sdi->conn;
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193 pbuf = devc->protocol_buf;
194
195 /* On the first run, we need to init the HID chip. */
bc653a56 196 if (devc->first_run) {
f0540611 197 if ((ret = hid_chip_init(sdi, dmm->baudrate)) != SR_OK) {
79081ec8 198 sr_err("HID chip init failed: %d.", ret);
bc653a56 199 return SR_ERR;
79081ec8 200 }
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201 memset(pbuf, 0x00, DMM_BUFSIZE);
202 devc->first_run = FALSE;
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203 }
204
205 memset(&buf, 0x00, CHUNK_SIZE);
206
207 /* Get data from EP2 using an interrupt transfer. */
208 ret = libusb_interrupt_transfer(
3ece1dff 209 usb->devhdl, /* libusb device handle */
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210 LIBUSB_ENDPOINT_IN | 2, /* EP2, IN */
211 (unsigned char *)&buf, /* receive buffer */
212 CHUNK_SIZE, /* wLength */
213 &len, /* actually received byte count */
214 1000 /* timeout (ms) */);
215
216 if (ret < 0) {
d4928d71 217 sr_err("USB receive error: %s.", libusb_error_name(ret));
bc653a56 218 return SR_ERR;
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219 }
220
221 if (len != CHUNK_SIZE) {
222 sr_err("Short packet: received %d/%d bytes.", len, CHUNK_SIZE);
223 /* TODO: Print the bytes? */
bc653a56 224 return SR_ERR;
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225 }
226
227 log_8byte_chunk((const uint8_t *)&buf);
228
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229 /* If there are no data bytes just return (without error). */
230 if (buf[0] == 0xf0)
231 return SR_OK;
232
233 devc->bufoffset = 0;
234
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235 /*
236 * Append the 1-7 data bytes of this chunk to pbuf.
237 *
238 * Special case:
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239 * DMMs with Cyrustek ES51922 chip and UT71x DMMs need serial settings
240 * of 7o1. The WCH CH9325 UART to USB/HID chip used in (some
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241 * versions of) the UNI-T UT-D04 cable however, will also send
242 * the parity bit to the host in the 8-byte data chunks. This bit
243 * is encoded in bit 7 of each of the 1-7 data bytes and must thus
8769478c 244 * be removed in order for the actual protocol parser to work properly.
4d7ddff7 245 */
bc653a56 246 num_databytes_in_chunk = buf[0] & 0x0f;
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247 for (i = 0; i < num_databytes_in_chunk; i++, devc->buflen++) {
248 pbuf[devc->buflen] = buf[1 + i];
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249 if ((dmm->packet_parse == sr_es519xx_19200_14b_parse) ||
250 (dmm->packet_parse == sr_ut71x_parse)) {
8769478c 251 /* Mask off the parity bit. */
4d7ddff7 252 pbuf[devc->buflen] &= ~(1 << 7);
8769478c 253 }
4d7ddff7 254 }
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255
256 /* Now look for packets in that data. */
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257 while ((devc->buflen - devc->bufoffset) >= dmm->packet_size) {
258 if (dmm->packet_valid(pbuf + devc->bufoffset)) {
bc653a56 259 log_dmm_packet(pbuf + devc->bufoffset);
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260 decode_packet(sdi, pbuf + devc->bufoffset);
261 devc->bufoffset += dmm->packet_size;
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262 } else {
263 devc->bufoffset++;
79081ec8 264 }
bc653a56 265 }
79081ec8 266
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267 /* Move remaining bytes to beginning of buffer. */
268 for (i = 0; i < devc->buflen - devc->bufoffset; i++)
269 pbuf[i] = pbuf[devc->bufoffset + i];
270 devc->buflen -= devc->bufoffset;
79081ec8 271
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272 return SR_OK;
273}
274
f0540611 275SR_PRIV int uni_t_dmm_receive_data(int fd, int revents, void *cb_data)
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276{
277 int ret;
278 struct sr_dev_inst *sdi;
279 struct dev_context *devc;
c8852687 280
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281 (void)fd;
282 (void)revents;
c8852687 283
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284 sdi = cb_data;
285 devc = sdi->priv;
c8852687 286
f0540611 287 if ((ret = get_and_handle_data(sdi)) != SR_OK)
bc653a56 288 return FALSE;
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289
290 /* Abort acquisition if we acquired enough samples. */
8a63a406 291 if (sr_sw_limits_check(&devc->limits))
695dc859 292 sdi->driver->dev_acquisition_stop(sdi);
c5ffac41 293
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294 return TRUE;
295}