* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <config.h>
#include "protocol.h"
#define MAX_PACKET_LEN 22
/* TODO: How to compute the checksum? Hardware seems to ignore it. */
/* Request reading. */
- written = serial_write(serial, &cmdout, sizeof(cmdout));
+ written = serial_write_blocking(serial, &cmdout, sizeof(cmdout),
+ serial_timeout(serial, sizeof(cmdout)));
if (written != sizeof(cmdout))
return SR_ERR;
int i;
uint8_t chksum = 0;
uint8_t *payload;
-
+
payload = (uint8_t *)(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, int len, float *floatval)
+static int parse_value(const char *txt, size_t len, float *floatval)
{
- int s, d;
- char str[32];
+ const char *txt_end;
+ char c, buf[32], *dst;
+ int ret;
- if (strstr(strbuf, "OL")) {
- sr_dbg("Overlimit.");
- *floatval = INFINITY;
- return SR_OK;
+ /*
+ * The input text is not NUL terminated, the checksum follows
+ * the value text field. Spaces may interfere with the text to
+ * number conversion, especially with exponent parsing. Copy the
+ * input data to a terminated text buffer and strip spaces in the
+ * process, before running ASCIIZ string operations.
+ */
+ if (len >= sizeof(buf)) {
+ sr_err("Insufficient text conversion buffer size.");
+ return SR_ERR_BUG;
+ }
+ txt_end = txt + len;
+ dst = &buf[0];
+ while (txt < txt_end && *txt) {
+ c = *txt++;
+ if (c == ' ')
+ continue;
+ *dst++ = c;
}
+ *dst = '\0';
- memset(str, 0, sizeof(str));
- /* Spaces may interfere with parsing the exponent. Strip them. */
- for (s = 0, d = 0; s < len; s++) {
- if (strbuf[s] != ' ')
- str[d++] = strbuf[s];
+ /* Check for overflow, or get the number value. */
+ if (strstr(buf, "+OL")) {
+ *floatval = +INFINITY;
+ return SR_OK;
}
- if (sr_atof_ascii(str, floatval) != SR_OK)
- return SR_ERR;
+ if (strstr(buf, "-OL")) {
+ *floatval = -INFINITY;
+ return SR_OK;
+ }
+ if (strstr(buf, "OL")) {
+ *floatval = INFINITY;
+ return SR_OK;
+ }
+ ret = sr_atof_ascii(buf, floatval);
+ if (ret != SR_OK)
+ return ret;
return SR_OK;
}
-static void parse_flags(const uint8_t *buf, struct brymen_flags *info)
+static void parse_flags(const uint8_t *bfunc, struct brymen_flags *info)
{
- info->is_low_batt = (buf[4 + 3] & (1 << 7)) != 0;
-
- info->is_decibel = (buf[4 + 1] & (1 << 5)) != 0;
- info->is_duty_cycle = (buf[4 + 1] & (1 << 3)) != 0;
- info->is_hertz = (buf[4 + 1] & (1 << 2)) != 0;
- info->is_amp = (buf[4 + 1] & (1 << 1)) != 0;
- info->is_beep = (buf[4 + 1] & (1 << 0)) != 0;
-
- info->is_ohm = (buf[4 + 0] & (1 << 7)) != 0;
- info->is_fahrenheit = (buf[4 + 0] & (1 << 6)) != 0;
- info->is_celsius = (buf[4 + 0] & (1 << 5)) != 0;
- info->is_diode = (buf[4 + 0] & (1 << 4)) != 0;
- info->is_capacitance = (buf[4 + 0] & (1 << 3)) != 0;
- info->is_volt = (buf[4 + 0] & (1 << 2)) != 0;
- info->is_dc = (buf[4 + 0] & (1 << 1)) != 0;
- info->is_ac = (buf[4 + 0] & (1 << 0)) != 0;
+ info->is_low_batt = (bfunc[3] & (1 << 7)) != 0;
+
+ info->is_decibel = (bfunc[1] & (1 << 5)) != 0;
+ info->is_duty_cycle = (bfunc[1] & (1 << 3)) != 0;
+ info->is_hertz = (bfunc[1] & (1 << 2)) != 0;
+ info->is_amp = (bfunc[1] & (1 << 1)) != 0;
+ info->is_beep = (bfunc[1] & (1 << 0)) != 0;
+
+ info->is_ohm = (bfunc[0] & (1 << 7)) != 0;
+ info->is_fahrenheit = (bfunc[0] & (1 << 6)) != 0;
+ info->is_celsius = (bfunc[0] & (1 << 5)) != 0;
+ info->is_diode = (bfunc[0] & (1 << 4)) != 0;
+ info->is_capacitance = (bfunc[0] & (1 << 3)) != 0;
+ info->is_volt = (bfunc[0] & (1 << 2)) != 0;
+ info->is_dc = (bfunc[0] & (1 << 1)) != 0;
+ info->is_ac = (bfunc[0] & (1 << 0)) != 0;
}
SR_PRIV int brymen_parse(const uint8_t *buf, float *floatval,
struct brymen_flags flags;
struct brymen_header *hdr;
uint8_t *bfunc;
- int asciilen;
+ const char *txt;
+ int txtlen;
+ char *p;
+ char *unit;
+ int ret;
(void)info;
hdr = (void *)buf;
bfunc = (uint8_t *)(buf + sizeof(struct brymen_header));
-
- 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);
- if (parse_value((const char *)(bfunc + 4), asciilen, floatval) != SR_OK)
+ txt = (const char *)&bfunc[4];
+ txtlen = hdr->len - 4;
+ sr_dbg("DMM bfunc: %02x %02x %02x %02x, text '%.*s'",
+ bfunc[3], bfunc[2], bfunc[1], bfunc[0], txtlen, txt);
+
+ memset(&flags, 0, sizeof(flags));
+ parse_flags(bfunc, &flags);
+ if (flags.is_decibel && flags.is_ohm) {
+ /*
+ * The reference impedance for the dBm function is in an
+ * unexpected format. Naive conversion of non-space chars
+ * gives incorrect results. Isolate the 4..1200 Ohms value
+ * instead, ignore the "0." and exponent parts of the
+ * response text.
+ */
+ if (strncmp(txt, " 0.", strlen(" 0.")) == 0 && strstr(txt, " E")) {
+ txt = &txt[strlen(" 0.")];
+ txtlen -= strlen(" 0.");
+ p = strchr(txt, 'E');
+ if (p)
+ *p = '\0';
+ }
+ }
+ if (flags.is_fahrenheit || flags.is_celsius) {
+ /*
+ * The value text in temperature mode includes the C/F
+ * suffix between the mantissa and the exponent, which
+ * breaks the text to number conversion. Example data:
+ * " 0.0217CE+3". Remove the C/F unit identifier.
+ */
+ unit = strchr(txt, flags.is_fahrenheit ? 'F' : 'C');
+ if (!unit)
+ return SR_ERR;
+ *unit = ' ';
+ }
+ ret = parse_value(txt, txtlen, floatval);
+ sr_dbg("floatval: %f, ret %d", *floatval, ret);
+ if (ret != SR_OK)
return SR_ERR;
+ analog->meaning->mqflags = 0;
if (flags.is_volt) {
- analog->mq = SR_MQ_VOLTAGE;
- analog->unit = SR_UNIT_VOLT;
+ analog->meaning->mq = SR_MQ_VOLTAGE;
+ analog->meaning->unit = SR_UNIT_VOLT;
}
if (flags.is_amp) {
- analog->mq = SR_MQ_CURRENT;
- analog->unit = SR_UNIT_AMPERE;
+ analog->meaning->mq = SR_MQ_CURRENT;
+ analog->meaning->unit = SR_UNIT_AMPERE;
}
if (flags.is_ohm) {
- if (flags.is_beep)
- analog->mq = SR_MQ_CONTINUITY;
+ if (flags.is_decibel)
+ analog->meaning->mq = SR_MQ_RESISTANCE;
+ else if (flags.is_beep)
+ analog->meaning->mq = SR_MQ_CONTINUITY;
else
- analog->mq = SR_MQ_RESISTANCE;
- analog->unit = SR_UNIT_OHM;
+ analog->meaning->mq = SR_MQ_RESISTANCE;
+ analog->meaning->unit = SR_UNIT_OHM;
}
if (flags.is_hertz) {
- analog->mq = SR_MQ_FREQUENCY;
- analog->unit = SR_UNIT_HERTZ;
+ analog->meaning->mq = SR_MQ_FREQUENCY;
+ analog->meaning->unit = SR_UNIT_HERTZ;
}
if (flags.is_duty_cycle) {
- analog->mq = SR_MQ_DUTY_CYCLE;
- analog->unit = SR_UNIT_PERCENTAGE;
+ analog->meaning->mq = SR_MQ_DUTY_CYCLE;
+ analog->meaning->unit = SR_UNIT_PERCENTAGE;
}
if (flags.is_capacitance) {
- analog->mq = SR_MQ_CAPACITANCE;
- analog->unit = SR_UNIT_FARAD;
+ analog->meaning->mq = SR_MQ_CAPACITANCE;
+ analog->meaning->unit = SR_UNIT_FARAD;
}
if (flags.is_fahrenheit) {
- analog->mq = SR_MQ_TEMPERATURE;
- analog->unit = SR_UNIT_FAHRENHEIT;
+ analog->meaning->mq = SR_MQ_TEMPERATURE;
+ analog->meaning->unit = SR_UNIT_FAHRENHEIT;
}
if (flags.is_celsius) {
- analog->mq = SR_MQ_TEMPERATURE;
- analog->unit = SR_UNIT_CELSIUS;
+ analog->meaning->mq = SR_MQ_TEMPERATURE;
+ analog->meaning->unit = SR_UNIT_CELSIUS;
}
if (flags.is_capacitance) {
- analog->mq = SR_MQ_CAPACITANCE;
- analog->unit = SR_UNIT_FARAD;
+ analog->meaning->mq = SR_MQ_CAPACITANCE;
+ analog->meaning->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.
+ * The high-end Brymen models have a configurable reference
+ * impedance for dBm measurements. When the meter's function
+ * is entered, or when the reference impedance is changed, the
+ * meter sends one packet with the value of the new reference.
+ * Both decibel and ohm flags are set in this case, so we must
+ * be careful to not clobber the resistance value from above,
+ * and only provide dBm when the measurement is shown and not
+ * its reference.
+ *
+ * The meter's response values also use an unexpected scale
+ * (always off by factor 1000, as if it was Watts not mW).
+ *
+ * Example responses:
+ * bfunc: 00 00 20 80, text ' 0. 800 E+1' (reference)
+ * bfunc: 00 00 20 00, text '-0.3702 E-1' (measurement)
*/
if (flags.is_decibel && !flags.is_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.
- */
+ analog->meaning->mq = SR_MQ_POWER;
+ analog->meaning->unit = SR_UNIT_DECIBEL_MW;
*floatval *= 1000;
}
if (flags.is_diode)
- analog->mqflags |= SR_MQFLAG_DIODE;
+ analog->meaning->mqflags |= SR_MQFLAG_DIODE | SR_MQFLAG_DC;
/* We can have both AC+DC in a single measurement. */
if (flags.is_ac)
- analog->mqflags |= SR_MQFLAG_AC;
+ analog->meaning->mqflags |= SR_MQFLAG_AC;
if (flags.is_dc)
- analog->mqflags |= SR_MQFLAG_DC;
+ analog->meaning->mqflags |= SR_MQFLAG_DC;
if (flags.is_low_batt)
- sr_info("Low battery!");
+ sr_warn("Low battery!");
return SR_OK;
}
projects / libsigrok.git / blobdiff