brymen-dmm: Add support for Brymen BM857

This patch might also work for a number of other Brymen models
-- 859(a), 867, 869---
including their respective rebadges from Greenlee, Extech, and Amprobe.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
This commit is contained in:
Alexandru Gagniuc 2012-11-26 17:09:05 -06:00 committed by Uwe Hermann
parent 20cbc7854d
commit 601fb67cc4
5 changed files with 776 additions and 59 deletions

View File

@ -24,6 +24,7 @@ noinst_LTLIBRARIES = libsigrok_hw_brymen_dmm.la
libsigrok_hw_brymen_dmm_la_SOURCES = \
api.c \
parser.c \
protocol.c \
protocol.h

View File

@ -18,42 +18,31 @@
*/
#include <glib.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include "libsigrok.h"
#include "libsigrok-internal.h"
#include "protocol.h"
static const int hwopts[] = {
SR_CONF_CONN,
SR_CONF_SERIALCOMM,
0,
};
static const int hwcaps[] = {
SR_CONF_MULTIMETER,
SR_CONF_LIMIT_SAMPLES,
SR_CONF_CONTINUOUS,
SR_CONF_LIMIT_MSEC,
0,
};
SR_PRIV struct sr_dev_driver brymen_dmm_driver_info;
static struct sr_dev_driver *di = &brymen_dmm_driver_info;
/* Properly close and free all devices. */
static int clear_instances(void)
{
struct sr_dev_inst *sdi;
struct drv_context *drvc;
struct dev_context *devc;
GSList *l;
if (!(drvc = di->priv))
return SR_OK;
for (l = drvc->instances; l; l = l->next) {
if (!(sdi = l->data))
continue;
if (!(devc = sdi->priv))
continue;
/* TODO */
sr_dev_inst_free(sdi);
}
g_slist_free(drvc->instances);
drvc->instances = NULL;
return SR_OK;
}
static int hw_init(void)
static int hw_init(struct sr_context *sr_ctx)
{
struct drv_context *drvc;
@ -62,17 +51,107 @@ static int hw_init(void)
return SR_ERR_MALLOC;
}
/* TODO */
drvc->sr_ctx = sr_ctx;
di->priv = drvc;
return SR_OK;
}
static void free_instance(void *inst)
{
struct sr_dev_inst *sdi;
struct dev_context *devc;
if (!(sdi = inst))
return;
if (!(devc = sdi->priv))
return;
sr_serial_dev_inst_free(devc->serial);
sr_dev_inst_free(sdi);
}
/* Properly close and free all devices. */
static int clear_instances(void)
{
struct drv_context *drvc;
if (!(drvc = di->priv))
return SR_OK;
g_slist_free_full(drvc->instances, free_instance);
drvc->instances = NULL;
return SR_OK;
}
static GSList *brymen_scan(const char *conn, const char *serialcomm)
{
struct sr_dev_inst *sdi;
struct dev_context *devc;
struct drv_context *drvc;
struct sr_probe *probe;
struct sr_serial_dev_inst *serial;
GSList *devices;
int ret;
if (!(serial = sr_serial_dev_inst_new(conn, serialcomm)))
return NULL;
if (serial_open(serial, SERIAL_RDWR|SERIAL_NONBLOCK) != SR_OK)
return NULL;
sr_info("Probing port %s.", conn);
devices = NULL;
/* Request reading */
if (brymen_packet_request(serial) == -1) {
sr_err("Unable to send command. code: %d.", errno);
goto scan_cleanup;
}
uint8_t buf[128];
size_t len = 128;
ret = brymen_stream_detect(serial, buf, &len, brymen_packet_length,
brymen_packet_is_valid, 1000, 9600);
if (ret != SR_OK)
goto scan_cleanup;
sr_info("Found device on port %s.", conn);
if (!(sdi = sr_dev_inst_new(0, SR_ST_INACTIVE, "Brymen", "BM85x", "")))
goto scan_cleanup;
if (!(devc = g_try_malloc0(sizeof(struct dev_context)))) {
sr_err("Device context malloc failed.");
goto scan_cleanup;
}
devc->serial = serial;
drvc = di->priv;
sdi->priv = devc;
sdi->driver = di;
if (!(probe = sr_probe_new(0, SR_PROBE_ANALOG, TRUE, "P1")))
goto scan_cleanup;
sdi->probes = g_slist_append(sdi->probes, probe);
drvc->instances = g_slist_append(drvc->instances, sdi);
devices = g_slist_append(devices, sdi);
scan_cleanup:
serial_close(serial);
return devices;
}
static GSList *hw_scan(GSList *options)
{
struct drv_context *drvc;
GSList *devices;
struct sr_config *src;
GSList *devices, *l;
const char *conn, *serialcomm;
(void)options;
@ -80,7 +159,29 @@ static GSList *hw_scan(GSList *options)
drvc = di->priv;
drvc->instances = NULL;
/* TODO */
conn = serialcomm = NULL;
for (l = options; l; l = l->next) {
src = l->data;
switch (src->key) {
case SR_CONF_CONN:
conn = src->value;
break;
case SR_CONF_SERIALCOMM:
serialcomm = src->value;
break;
}
}
if (!conn) {
return NULL;
}
if (serialcomm) {
/* Use the provided comm specs. */
devices = brymen_scan(conn, serialcomm);
} else {
/* But 9600 8N1 should work all of the time */
devices = brymen_scan(conn, "9600/8n1/dtr=1/rts=1");
}
return devices;
}
@ -96,14 +197,34 @@ static GSList *hw_dev_list(void)
static int hw_dev_open(struct sr_dev_inst *sdi)
{
/* TODO */
struct dev_context *devc;
if (!(devc = sdi->priv)) {
sr_err("sdi->priv was NULL.");
return SR_ERR_BUG;
}
if (serial_open(devc->serial, SERIAL_RDWR | SERIAL_NONBLOCK) != SR_OK)
return SR_ERR;
sdi->status = SR_ST_ACTIVE;
return SR_OK;
}
static int hw_dev_close(struct sr_dev_inst *sdi)
{
/* TODO */
struct dev_context *devc;
if (!(devc = sdi->priv)) {
sr_err("sdi->priv was NULL.");
return SR_ERR_BUG;
}
if (devc->serial && devc->serial->fd != -1) {
serial_close(devc->serial);
sdi->status = SR_ST_INACTIVE;
}
return SR_OK;
}
@ -112,27 +233,33 @@ static int hw_cleanup(void)
{
clear_instances();
/* TODO */
return SR_OK;
}
static int hw_info_get(int info_id, const void **data,
static int config_list(int key, const void **data,
const struct sr_dev_inst *sdi)
{
switch (info_id) {
/* TODO */
(void)sdi;
switch (key) {
case SR_CONF_SCAN_OPTIONS:
*data = hwopts;
break;
case SR_CONF_DEVICE_OPTIONS:
*data = hwcaps;
break;
default:
sr_err("Unknown info_id: %d.", info_id);
sr_err("Unknown config key: %d.", key);
return SR_ERR_ARG;
}
return SR_OK;
}
static int hw_dev_config_set(const struct sr_dev_inst *sdi, int hwcap,
const void *value)
static int hw_dev_config_set(int id, const void *value,
const struct sr_dev_inst *sdi)
{
struct dev_context *devc;
int ret;
if (sdi->status != SR_ST_ACTIVE) {
@ -140,11 +267,21 @@ static int hw_dev_config_set(const struct sr_dev_inst *sdi, int hwcap,
return SR_ERR;
}
if (!(devc = sdi->priv)) {
sr_err("sdi->priv was NULL.");
return SR_ERR_BUG;
}
ret = SR_OK;
switch (hwcap) {
/* TODO */
switch (id) {
case SR_CONF_LIMIT_SAMPLES:
devc->limit_samples = *(const uint64_t*)value;
break;
case SR_CONF_LIMIT_MSEC:
devc->limit_msec = *(const uint64_t*)value;
break;
default:
sr_err("Unknown hardware capability: %d.", hwcap);
sr_err("Unknown hardware capability: %d.", id);
ret = SR_ERR_ARG;
}
@ -154,29 +291,73 @@ static int hw_dev_config_set(const struct sr_dev_inst *sdi, int hwcap,
static int hw_dev_acquisition_start(const struct sr_dev_inst *sdi,
void *cb_data)
{
/* TODO */
struct sr_datafeed_packet packet;
struct sr_datafeed_header header;
struct dev_context *devc;
if (!(devc = sdi->priv)) {
sr_err("sdi->priv was NULL.");
return SR_ERR_BUG;
}
sr_dbg("Starting acquisition.");
devc->cb_data = cb_data;
/*
* Reset the number of samples to take. If we've already collected our
* quota, but we start a new session, and don't reset this, we'll just
* quit without acquiring any new samples.
*/
devc->num_samples = 0;
devc->starttime = g_get_monotonic_time();
/* Send header packet to the session bus. */
sr_dbg("Sending SR_DF_HEADER.");
packet.type = SR_DF_HEADER;
packet.payload = &header;
header.feed_version = 1;
gettimeofday(&header.starttime, NULL);
sr_session_send(devc->cb_data, &packet);
/* Poll every 50ms, or whenever some data comes in. */
sr_source_add(devc->serial->fd, G_IO_IN, 50,
brymen_dmm_receive_data, (void *)sdi);
return SR_OK;
}
static int hw_dev_acquisition_stop(const struct sr_dev_inst *sdi,
void *cb_data)
static int hw_dev_acquisition_stop(struct sr_dev_inst *sdi, void *cb_data)
{
(void)cb_data;
struct sr_datafeed_packet packet;
struct dev_context *devc;
if (sdi->status != SR_ST_ACTIVE) {
sr_err("Device inactive, can't stop acquisition.");
return SR_ERR;
}
/* TODO */
if (!(devc = sdi->priv)) {
sr_err("sdi->priv was NULL.");
return SR_ERR_BUG;
}
sr_dbg("Stopping acquisition.");
sr_source_remove(devc->serial->fd);
hw_dev_close((struct sr_dev_inst *)sdi);
/* Send end packet to the session bus. */
sr_dbg("Sending SR_DF_END.");
packet.type = SR_DF_END;
sr_session_send(cb_data, &packet);
return SR_OK;
}
SR_PRIV struct sr_dev_driver brymen_dmm_driver_info = {
.name = "brymen-dmm",
.longname = "brymen-dmm",
.longname = "Brymen BM850 series",
.api_version = 1,
.init = hw_init,
.cleanup = hw_cleanup,
@ -185,8 +366,8 @@ SR_PRIV struct sr_dev_driver brymen_dmm_driver_info = {
.dev_clear = clear_instances,
.dev_open = hw_dev_open,
.dev_close = hw_dev_close,
.info_get = hw_info_get,
.dev_config_set = hw_dev_config_set,
.config_list = config_list,
.config_set = hw_dev_config_set,
.dev_acquisition_start = hw_dev_acquisition_start,
.dev_acquisition_stop = hw_dev_acquisition_stop,
.priv = NULL,

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@ -0,0 +1,279 @@
/*
* This file is part of the sigrok project.
*
* Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
*
* 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 3 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/>.
*/
#include "protocol.h"
#include <stdlib.h>
#include <string.h>
#include <math.h>
/*
* Flags passed from the DMM.
*/
struct brymen_flags {
gboolean low_batt;
gboolean decibel, duty_cycle, hertz, amp, beep, ohm, fahrenheit;
gboolean celsius, capacitance, diode, volt, dc, ac;
};
struct bm850_command {
uint8_t dle;
uint8_t stx;
uint8_t cmd;
uint8_t arg[2];
uint8_t checksum;
uint8_t dle2;
uint8_t etx;
};
struct brymen_header {
uint8_t dle;
uint8_t stx;
uint8_t cmd;
uint8_t len;
};
struct brymen_tail {
uint8_t checksum;
uint8_t dle;
uint8_t etx;
};
/*
* We only have one command because we only support the BM-857. However, the
* driver is easily extensible to support more models, as the protocols are very
* similar.
*/
enum {
BM_CMD_REQUEST_READING = 0x00,
};
static int bm_send_command(uint8_t command, uint8_t arg1, uint8_t arg2,
struct sr_serial_dev_inst *serial)
{
struct bm850_command cmdout = {
.dle = 0x10, .stx = 0x02,
.cmd = command,
.arg = {arg1, arg2},
.checksum = arg1^arg2, .dle2 = 0x10, .etx = 0x03};
int written;
/* TODO: How do we compute the checksum? Hardware seems to ignore it */
/* Request reading */
written = serial_write(serial, &cmdout, sizeof(cmdout));
if(written != sizeof(cmdout))
return SR_ERR;
return SR_OK;
}
SR_PRIV int brymen_packet_request(struct sr_serial_dev_inst *serial)
{
return bm_send_command(BM_CMD_REQUEST_READING, 0, 0, serial);
}
SR_PRIV int brymen_packet_length(const uint8_t *buf, int *len)
{
struct brymen_header *hdr;
const int brymen_max_packet_len = 22;
int packet_len;
const size_t buflen = *len;
hdr = (void*)buf;
/* Did we receive a complete header yet? */
if (buflen < sizeof(*hdr) )
return PACKET_NEED_MORE_DATA;
if (hdr->dle != 0x10 || hdr->stx != 0x02)
return PACKET_INVALID_HEADER;
/* Our packet includes the header, the payload, and the tail */
packet_len = sizeof(*hdr) + hdr->len + sizeof(struct brymen_tail);
/* In case we pick up an invalid header, limit our search */
if (packet_len > brymen_max_packet_len) {
sr_spew("Header specifies an invalid payload length: %i.",
hdr->len);
return PACKET_INVALID_HEADER;
}
*len = packet_len;
sr_spew("Expecting a %d-byte packet.", *len);
return PACKET_HEADER_OK;
}
SR_PRIV gboolean brymen_packet_is_valid(const uint8_t *buf)
{
struct brymen_header *hdr;
struct brymen_tail *tail;
int i;
uint8_t chksum = 0;
const uint8_t *payload = buf + sizeof(struct brymen_header);
hdr = (void*)buf;
tail = (void*)(payload + hdr->len);
for (i = 0; i< hdr->len; i++)
chksum ^= payload[i];
if (tail->checksum != chksum) {
sr_dbg("Packet has invalid checksum 0x%.2x. Expected 0x%.2x",
chksum, tail->checksum);
return FALSE;
}
return TRUE;
}
static int parse_value(const char *strbuf, const int len, float *floatval)
{
int s, d;
char str[32];
if (strstr(strbuf, "OL")) {
sr_dbg("Overlimit.");
*floatval = INFINITY;
return SR_OK;
}
memset(str, 0, sizeof(str));
/* Spaces may interfere with strtod parsing the exponent. Strip them */
for (s = 0, d = 0; s < len; s++)
if (strbuf[s] != ' ')
str[d++] = strbuf[s];
/* YES, it's that simple !*/
*floatval = strtod(str, NULL);
return SR_OK;
}
static void parse_flags(const uint8_t *buf, struct brymen_flags *info)
{
const uint8_t * bfunc = buf + sizeof(struct brymen_header);
info->low_batt = (bfunc[3] & (1 << 7)) != 0;
info->decibel = (bfunc[1] & (1 << 5)) != 0;
info->duty_cycle = (bfunc[1] & (1 << 3)) != 0;
info->hertz = (bfunc[1] & (1 << 2)) != 0;
info->amp = (bfunc[1] & (1 << 1)) != 0;
info->beep = (bfunc[1] & (1 << 0)) != 0;
info->ohm = (bfunc[0] & (1 << 7)) != 0;
info->fahrenheit = (bfunc[0] & (1 << 6)) != 0;
info->celsius = (bfunc[0] & (1 << 5)) != 0;
info->diode = (bfunc[0] & (1 << 4)) != 0;
info->capacitance = (bfunc[0] & (1 << 3)) != 0;
info->volt = (bfunc[0] & (1 << 2)) != 0;
info->dc = (bfunc[0] & (1 << 1)) != 0;
info->ac = (bfunc[0] & (1 << 0)) != 0;
}
SR_PRIV int sr_brymen_parse(const uint8_t *buf, float *floatval,
struct sr_datafeed_analog *analog, void *info)
{
struct brymen_flags flags;
struct brymen_header *hdr = (void*) buf;
const uint8_t *bfunc = buf + sizeof(struct brymen_header);
int asciilen;
(void)info;
analog->mqflags = 0;
/* Give some debug info about the package */
asciilen = hdr->len - 4;
sr_dbg("DMM flags: %.2x %.2x %.2x %.2x",
bfunc[3], bfunc[2], bfunc[1], bfunc[0]);
/* Value is an ASCII string */
sr_dbg("DMM packet: \"%.*s\"", asciilen, bfunc + 4);
parse_flags(buf, &flags);
parse_value((const char*)(bfunc + 4), asciilen, floatval);
if (flags.volt) {
analog->mq = SR_MQ_VOLTAGE;
analog->unit = SR_UNIT_VOLT;
}
if (flags.amp) {
analog->mq = SR_MQ_CURRENT;
analog->unit = SR_UNIT_AMPERE;
}
if (flags.ohm) {
if (flags.beep)
analog->mq = SR_MQ_CONTINUITY;
else
analog->mq = SR_MQ_RESISTANCE;
analog->unit = SR_UNIT_OHM;
}
if (flags.hertz) {
analog->mq = SR_MQ_FREQUENCY;
analog->unit = SR_UNIT_HERTZ;
}
if (flags.duty_cycle) {
analog->mq = SR_MQ_DUTY_CYCLE;
analog->unit = SR_UNIT_PERCENTAGE;
}
if (flags.capacitance) {
analog->mq = SR_MQ_CAPACITANCE;
analog->unit = SR_UNIT_FARAD;
}
if (flags.fahrenheit) {
analog->mq = SR_MQ_TEMPERATURE;
analog->unit = SR_UNIT_FAHRENHEIT;
}
if (flags.celsius) {
analog->mq = SR_MQ_TEMPERATURE;
analog->unit = SR_UNIT_CELSIUS;
}
if (flags.capacitance) {
analog->mq = SR_MQ_CAPACITANCE;
analog->unit = SR_UNIT_FARAD;
}
/*
* The high-end brymen models have a configurable reference impedance.
* When the reference impedance is changed, the DMM sends one packet
* with the value of the new reference impedance. Both decibel and ohm
* flags are set in this case, so we must be careful to correctly
* identify the value as ohm, not dBmW
*/
if (flags.decibel && !flags.ohm) {
analog->mq = SR_MQ_POWER;
analog->unit = SR_UNIT_DECIBEL_MW;
/*
* For some reason, dBm measurements are sent by the multimeter
* with a value three orders of magnitude smaller than the
* displayed value.
* */
*floatval *= 1000;
}
if (flags.diode)
analog->mqflags |= SR_MQFLAG_DIODE;
/* We can have both AC+DC in a single measurement */
if (flags.ac)
analog->mqflags |= SR_MQFLAG_AC;
if (flags.dc)
analog->mqflags |= SR_MQFLAG_DC;
if (flags.low_batt)
sr_info("Low battery!");
return SR_OK;
}

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@ -17,16 +17,109 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <glib.h>
#include "libsigrok.h"
#include "libsigrok-internal.h"
#include "protocol.h"
#include <string.h>
/* --- parser.c --- */
SR_PRIV int sr_brymen_parse(const uint8_t *buf, float *floatval,
struct sr_datafeed_analog *analog, void *info);
static void handle_packet(const uint8_t *buf, struct sr_dev_inst *sdi)
{
float floatval;
struct dev_context *devc;
struct sr_datafeed_packet packet;
struct sr_datafeed_analog analog;
devc = sdi->priv;
analog.num_samples = 1;
analog.mq = -1;
sr_brymen_parse(buf, &floatval, &analog, NULL);
analog.data = &floatval;
analog.probes = sdi->probes;
if (analog.mq != -1) {
/* Got a measurement. */
packet.type = SR_DF_ANALOG;
packet.payload = &analog;
sr_session_send(devc->cb_data, &packet);
devc->num_samples++;
}
}
static void handle_new_data(struct sr_dev_inst *sdi)
{
struct dev_context *devc;
int len, status, offset = 0;
devc = sdi->priv;
/* Try to get as much data as the buffer can hold. */
len = DMM_BUFSIZE - devc->buflen;
len = serial_read(devc->serial, devc->buf + devc->buflen, len);
if (len < 1) {
sr_err("Serial port read error: %d.", len);
return;
}
devc->buflen += len;
status = PACKET_INVALID_HEADER;
/* Now look for packets in that data. */
while (status != PACKET_NEED_MORE_DATA) {
/* We don't have a header, look for one */
if (devc->next_packet_len == 0) {
len = devc->buflen - offset;
status = brymen_packet_length(devc->buf + offset, &len);
if (status == PACKET_HEADER_OK) {
/* We know how large the packet will be */
devc->next_packet_len = len;
} else if (status == PACKET_NEED_MORE_DATA) {
/* We did not yet receive the complete header */
devc->next_packet_len = 0;
break;
} else {
/* Invalid header. Move on */
devc->next_packet_len = 0;
offset++;
continue;
}
}
/* We know how the packet size, but did we receive all of it? */
if (devc->buflen - offset < devc->next_packet_len)
break;
/* We should have a full packet here, so we can check it */
if (brymen_packet_is_valid(devc->buf + offset)) {
handle_packet(devc->buf + offset, sdi);
offset += devc->next_packet_len;
} else {
offset++;
}
/* We are done with this packet. Look for a new one. */
devc->next_packet_len = 0;
}
/* If we have any data left, move it to the beginning of our buffer. */
memmove(devc->buf, devc->buf + offset, devc->buflen - offset);
devc->buflen -= offset;
}
SR_PRIV int brymen_dmm_receive_data(int fd, int revents, void *cb_data)
{
const struct sr_dev_inst *sdi;
struct sr_dev_inst *sdi;
struct dev_context *devc;
int ret;
int64_t time;
(void)fd;
if (!(sdi = cb_data))
return TRUE;
@ -35,8 +128,134 @@ SR_PRIV int brymen_dmm_receive_data(int fd, int revents, void *cb_data)
return TRUE;
if (revents == G_IO_IN) {
/* TODO */
/* Serial data arrived. */
handle_new_data(sdi);
} else {
/* Timeout, send another packet request. */
ret = brymen_packet_request(devc->serial);
if (ret < 0) {
sr_err("Failed to request packet: %d.", ret);
return FALSE;
}
}
if (devc->limit_samples && devc->num_samples >= devc->limit_samples) {
sr_info("Requested number of samples reached, stopping.");
sdi->driver->dev_acquisition_stop(sdi, cb_data);
return TRUE;
}
if (devc->limit_msec) {
time = (g_get_monotonic_time() - devc->starttime) / 1000;
if (time > (int64_t)devc->limit_msec) {
sr_info("Requested time limit reached, stopping.");
sdi->driver->dev_acquisition_stop(sdi, cb_data);
return TRUE;
}
}
return TRUE;
}
/**
* Try to find a valid packet in a serial data stream.
*
* @param serial Previously initialized serial port structure.
* @param buf Buffer containing the bytes to write.
* @param buflen Size of the buffer.
* @param packet_size Callback that assesses the size of the incoming packet/
* @param is_valid Callback that assesses whether the packet is valid or not.
* @param timeout_ms The timeout after which, if no packet is detected, to
* abort scanning.
* @param baudrate The baudrate of the serial port. This parameter is not
* critical, but it helps fine tune the serial port polling
* delay.
*
* @return SR_OK if a valid packet is found within the given timeout,
* SR_ERR upon failure.
*/
SR_PRIV int brymen_stream_detect(struct sr_serial_dev_inst *serial,
uint8_t *buf, size_t *buflen,
packet_length_t get_packet_size,
packet_valid_t is_valid,
uint64_t timeout_ms, int baudrate)
{
int64_t start, time, byte_delay_us;
size_t ibuf, i, maxlen;
int status, len, packet_len, stream_len;
maxlen = *buflen;
sr_dbg("Detecting packets on FD %d (timeout = %" PRIu64
"ms, baudrate = %d).", serial->fd, timeout_ms, baudrate);
/* Assume 8n1 transmission. That is 10 bits for every byte. */
byte_delay_us = 10 * (1000000 / baudrate);
start = g_get_monotonic_time();
packet_len = i = ibuf = len = 0;
while (ibuf < maxlen) {
len = serial_read(serial, &buf[ibuf], maxlen - ibuf);
if (len > 0) {
ibuf += len;
sr_spew("Read %d bytes", len);
}
time = g_get_monotonic_time() - start;
time /= 1000;
stream_len = ibuf - i;
if (stream_len > 0 && packet_len == 0) {
/* How large of a packet are we expecting? */
packet_len = stream_len;
status = get_packet_size(&buf[i], &packet_len);
switch(status) {
case PACKET_HEADER_OK:
/* We know how much data we need to wait for */
break;
case PACKET_NEED_MORE_DATA:
/* We did not receive the full header */
packet_len = 0;
break;
case PACKET_INVALID_HEADER:
default:
/*
* We had enough data, but here was an error in
* parsing the header. Restart parsing from the
* next byte
*/
packet_len = 0;
i++;
break;
}
}
if ( (stream_len >= packet_len) && (packet_len != 0) ) {
/* We have at least a packet's worth of data. */
if (is_valid(&buf[i])) {
sr_spew("Found valid %d-byte packet after "
"%" PRIu64 "ms.", packet_len, time);
*buflen = ibuf;
return SR_OK;
} else {
sr_spew("Got %d bytes, but not a valid "
"packet.", packet_len);
}
/* Not a valid packet. Continue searching. */
i++;
packet_len = 0;
}
if (time >= (int64_t)timeout_ms) {
/* Timeout */
sr_dbg("Detection timed out after %dms.", time);
break;
}
g_usleep(byte_delay_us);
}
*buflen = ibuf;
sr_err("Didn't find a valid packet (read %d bytes).", ibuf);
return SR_ERR;
}

View File

@ -33,6 +33,15 @@
#define sr_warn(s, args...) sr_warn(DRIVER_LOG_DOMAIN s, ## args)
#define sr_err(s, args...) sr_err(DRIVER_LOG_DOMAIN s, ## args)
#define DMM_BUFSIZE 256
enum packet_len_status {
PACKET_HEADER_OK,
PACKET_NEED_MORE_DATA,
PACKET_INVALID_HEADER,
};
/** Private, per-device-instance driver context. */
struct dev_context {
/** The current sampling limit (in number of samples). */
@ -46,8 +55,36 @@ struct dev_context {
/** The current number of already received samples. */
uint64_t num_samples;
/** Start time of acquisition session */
int64_t starttime;
struct sr_serial_dev_inst *serial;
uint8_t buf[DMM_BUFSIZE];
int bufoffset;
int buflen;
int next_packet_len;
};
SR_PRIV int brymen_dmm_receive_data(int fd, int revents, void *cb_data);
/**
* Callback that assesses the size and status of the incoming packet
*
* @return PACKET_HEADER_OK - This is a proper packet header.
* PACKET_NEED_MORE_DATA The buffer does not contain the entire header
* PACKET_INVALID_HEADER Not a valid start of packet.
*/
typedef int (*packet_length_t)(const uint8_t *buf, int *len);
SR_PRIV int brymen_dmm_receive_data(int fd, int revents, void *cb_data);
SR_PRIV int brymen_packet_request(struct sr_serial_dev_inst *serial);
SR_PRIV int brymen_packet_length(const uint8_t *buf, int *len);
SR_PRIV gboolean brymen_packet_is_valid(const uint8_t *buf);
SR_PRIV int brymen_stream_detect(struct sr_serial_dev_inst *serial,
uint8_t *buf, size_t *buflen,
packet_length_t get_packet_size,
packet_valid_t is_valid,
uint64_t timeout_ms, int baudrate);
#endif