output/csv: use intermediate time_t var, silence compiler warning

[libsigrok.git] / src / dmm / bm86x.c

diff --git a/src/dmm/bm86x.c b/src/dmm/bm86x.c
index 3cfe586db7bdb978b4be29ddf4de8e36c5330f81..c160a88c033fc452b0e740a94d196700ba81818d 100644 (file)
--- a/src/dmm/bm86x.c
+++ b/src/dmm/bm86x.c
@@ -23,9 +23,10 @@
  *
  * Brymen BM86x serial protocol parser. The USB protocol (for the cable)
  * and the packet description (for the meter) were retrieved from:
- * http://brymen.com/product-html/Download2.html
- * http://brymen.com/product-html/PD02BM860s_protocolDL.html
- * http://brymen.com/product-html/images/DownloadList/ProtocolList/BM860-BM860s_List/BM860-BM860s-500000-count-dual-display-DMMs-protocol.pdf
+ * http://www.brymen.com/Download2.html
+ * http://www.brymen.com/PD02BM860s_protocolDL.html
+ * http://www.brymen.com/images/DownloadList/ProtocolList/BM860-BM860s_List/BM860-BM860s-500000-count-dual-display-DMMs-protocol.pdf
+ * http://web.archive.org/web/20191231053213/http://www.brymen.com/images/DownloadList/ProtocolList/BM860-BM860s_List/BM860-BM860s-500000-count-dual-display-DMMs-protocol.pdf
  */
 
 #include <config.h>
@@ -41,7 +42,6 @@ SR_PRIV int sr_brymen_bm86x_packet_request(struct sr_serial_dev_inst *serial)
 {
        static const uint8_t request[] = { 0x00, 0x00, 0x86, 0x66, };
 
-       sr_spew("%s() sending request", __func__);
        serial_write_nonblocking(serial, request, sizeof(request));
 
        return SR_OK;
@@ -60,6 +60,22 @@ SR_PRIV gboolean sr_brymen_bm86x_packet_valid(const uint8_t *buf)
        if (buf[19] != 0x86)
                return FALSE;
 
+       /*
+        * 2021-05 update: The devices that we have seen in the field do
+        * provide four bytes which we can synchronize to. Which happens
+        * to match the bm52x and bm82x devices' protocol. This condition
+        * is not documented by the vendor, but improves reliability of
+        * the re-synchronization for slight offsets, which were seen
+        * in the field, and which would have kept failing in an earlier
+        * implementation.
+        */
+       if (buf[16] != 0x86)
+               return FALSE;
+       if (buf[17] != 0x86)
+               return FALSE;
+       if (buf[18] != 0x86)
+               return FALSE;
+
        return TRUE;
 }
 
@@ -164,6 +180,7 @@ static void brymen_bm86x_parse(const uint8_t *buf, float *floatval,
        int ret, digits, is_diode, over_limit, scale;
        uint8_t ind1, ind15;
 
+       temp_unit = '\0';
        if (ch_idx == 0) {
                /*
                 * Main display. Note that _some_ of the second display's
@@ -212,7 +229,7 @@ static void brymen_bm86x_parse(const uint8_t *buf, float *floatval,
                } else if (buf[15] & 0x80) {
                        analog->meaning->mq = SR_MQ_DUTY_CYCLE;
                        analog->meaning->unit = SR_UNIT_PERCENTAGE;
-               } else if (buf[ 2] & 0x0a) {
+               } else if ((buf[2] & 0x0a) && temp_unit) {
                        analog->meaning->mq = SR_MQ_TEMPERATURE;
                        if (temp_unit == 'F')
                                analog->meaning->unit = SR_UNIT_FAHRENHEIT;
@@ -278,9 +295,16 @@ static void brymen_bm86x_parse(const uint8_t *buf, float *floatval,
                analog->encoding->digits  = digits;
                analog->spec->spec_digits = digits;
        } else if (ch_idx == 1) {
-               /* Secondary display. */
+               /*
+                * Secondary display. Also inspect _some_ primary display
+                * data, to determine the secondary display's validity.
+                */
+               (void)brymen_bm86x_parse_digits(&buf[2], 6, txtbuf,
+                       NULL, &temp_unit, NULL, 0x80);
                ret = brymen_bm86x_parse_digits(&buf[9], 4, txtbuf,
-                       floatval, &temp_unit, &digits, 0x10);
+                       floatval, NULL, &digits, 0x10);
+               if (ret != SR_OK)
+                       return;
 
                /* SI unit. */
                if (buf[14] & 0x08) {
@@ -295,7 +319,7 @@ static void brymen_bm86x_parse(const uint8_t *buf, float *floatval,
                } else if (buf[14] & 0x04) {
                        analog->meaning->mq = SR_MQ_FREQUENCY;
                        analog->meaning->unit = SR_UNIT_HERTZ;
-               } else if (buf[9] & 0x40) {
+               } else if ((buf[9] & 0x40) && temp_unit) {
                        analog->meaning->mq = SR_MQ_TEMPERATURE;
                        if (temp_unit == 'F')
                                analog->meaning->unit = SR_UNIT_FAHRENHEIT;