hantek-6xxx: properly set encoding digits

diff --git a/src/hardware/hantek-6xxx/api.c b/src/hardware/hantek-6xxx/api.c
index 55cf5fdfe91313ec3474317b1fb0894f3a678e61..349b557b7eaa91d3937548ea21bad0de3097e475 100644 (file)
--- a/src/hardware/hantek-6xxx/api.c
+++ b/src/hardware/hantek-6xxx/api.c
@@ -18,6 +18,7 @@
  */
 
 #include <config.h>
+#include <math.h>
 #include "protocol.h"
 
 /* Max time in ms before we want to check on USB events */
@@ -561,55 +562,58 @@ static void send_chunk(struct sr_dev_inst *sdi, unsigned char *buf,
        struct sr_analog_meaning meaning;
        struct sr_analog_spec spec;
        struct dev_context *devc = sdi->priv;
-       int num_channels, data_offset, i;
+       GSList *channels = devc->enabled_channels;
 
-       const float ch1_bit = RANGE(0) / 255;
-       const float ch2_bit = RANGE(1) / 255;
-       const float ch1_center = RANGE(0) / 2;
-       const float ch2_center = RANGE(1) / 2;
-
-       const gboolean ch1_ena = !!devc->ch_enabled[0];
-       const gboolean ch2_ena = !!devc->ch_enabled[1];
+       const float ch_bit[] = { RANGE(0) / 255, RANGE(1) / 255 };
+       const float ch_center[] = { RANGE(0) / 2, RANGE(1) / 2 };
 
        sr_analog_init(&analog, &encoding, &meaning, &spec, 0);
 
-       num_channels = (ch1_ena && ch2_ena) ? 2 : 1;
        packet.type = SR_DF_ANALOG;
        packet.payload = &analog;
 
-       analog.meaning->channels = devc->enabled_channels;
        analog.num_samples = num_samples;
        analog.meaning->mq = SR_MQ_VOLTAGE;
        analog.meaning->unit = SR_UNIT_VOLT;
        analog.meaning->mqflags = 0;
 
-       analog.data = g_try_malloc(analog.num_samples * sizeof(float) * num_channels);
+       analog.data = g_try_malloc(num_samples * sizeof(float));
        if (!analog.data) {
                sr_err("Analog data buffer malloc failed.");
                devc->dev_state = STOPPING;
                return;
        }
 
-       data_offset = 0;
-       for (i = 0; i < num_samples; i++) {
-               /*
-                * The device always sends data for both channels. If a channel
-                * is disabled, it contains a copy of the enabled channel's
-                * data. However, we only send the requested channels to
-                * the bus.
-                *
-                * Voltage values are encoded as a value 0-255, where the
-                * value is a point in the range represented by the vdiv
-                * setting. There are 10 vertical divs, so e.g. 500mV/div
-                * represents 5V peak-to-peak where 0 = -2.5V and 255 = +2.5V.
-                */
-               if (ch1_ena)
-                       ((float *)analog.data)[data_offset++] = (ch1_bit * *(buf + i * 2) - ch1_center);
-               if (ch2_ena)
-                       ((float *)analog.data)[data_offset++] = (ch2_bit * *(buf + i * 2 + 1) - ch2_center);
-       }
+       for (int ch = 0; ch < 2; ch++) {
+               if (!devc->ch_enabled[ch])
+                       continue;
 
-       sr_session_send(sdi, &packet);
+               float vdivlog = log10f(ch_bit[ch]);
+               int digits = -(int)vdivlog + (vdivlog < 0.0);
+               analog.encoding->digits = digits;
+               analog.spec->spec_digits = digits;
+               analog.meaning->channels = g_slist_append(NULL, channels->data);
+
+               for (int i = 0; i < num_samples; i++) {
+                       /*
+                        * The device always sends data for both channels. If a channel
+                        * is disabled, it contains a copy of the enabled channel's
+                        * data. However, we only send the requested channels to
+                        * the bus.
+                        *
+                        * Voltage values are encoded as a value 0-255, where the
+                        * value is a point in the range represented by the vdiv
+                        * setting. There are 10 vertical divs, so e.g. 500mV/div
+                        * represents 5V peak-to-peak where 0 = -2.5V and 255 = +2.5V.
+                        */
+                       ((float *)analog.data)[i] = ch_bit[ch] * *(buf + i * 2 + ch) - ch_center[ch];
+               }
+
+               sr_session_send(sdi, &packet);
+               g_slist_free(analog.meaning->channels);
+
+               channels = channels->next;
+       }
        g_free(analog.data);
 }