diff --git a/CMakeLists.txt b/CMakeLists.txt
index dd410cbf..76575bf6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -347,6 +347,7 @@ set(DSView_SOURCES
     DSView/pv/dialogs/decoderoptionsdlg.cpp
     DSView/pv/utility/encoding.cpp
     DSView/pv/utility/path.cpp
+    DSView/pv/utility/array.cpp
     DSView/pv/deviceagent.cpp
     DSView/pv/ui/langresource.cpp
 )
@@ -439,6 +440,7 @@ set(DSView_HEADERS
     DSView/pv/dialogs/decoderoptionsdlg.h
     DSView/pv/utility/encoding.h
     DSView/pv/utility/path.h
+    DSView/pv/utility/array.h
     DSView/pv/deviceagent.h
 )
  
diff --git a/DSView/pv/data/decoderstack.cpp b/DSView/pv/data/decoderstack.cpp
index a1c9f43d..393c429f 100644
--- a/DSView/pv/data/decoderstack.cpp
+++ b/DSView/pv/data/decoderstack.cpp
@@ -448,7 +448,7 @@ void DecoderStack::do_decode_work()
         }
     }
 
-	if (!data == NULL)
+	if (data == NULL)
 		return;
 
 	// Check we have a snapshot of data
diff --git a/DSView/pv/data/logicsnapshot.cpp b/DSView/pv/data/logicsnapshot.cpp
index 26ef55d1..35025d39 100644
--- a/DSView/pv/data/logicsnapshot.cpp
+++ b/DSView/pv/data/logicsnapshot.cpp
@@ -28,6 +28,7 @@
 #include "logicsnapshot.h"
 #include "../dsvdef.h"
 #include "../log.h"
+#include "../utility/array.h"
 
 using namespace std;
 
@@ -48,9 +49,11 @@ const uint64_t LogicSnapshot::LevelOffset[LogicSnapshot::ScaleLevel] = {
 };
 
 LogicSnapshot::LogicSnapshot() :
-    Snapshot(1, 0, 0),
-    _block_num(0)
+    Snapshot(1, 0, 0)
 {
+    _channel_num = 0;
+    _block_num = 0;
+    _total_sample_count = 0;
 }
 
 LogicSnapshot::~LogicSnapshot()
@@ -93,7 +96,6 @@ void LogicSnapshot::init_all()
     _data = NULL;
     _memory_failed = false;
     _last_ended = true;
-    _times = 0;
 }
 
 void LogicSnapshot::clear()
@@ -156,23 +158,23 @@ void LogicSnapshot::first_payload(const sr_datafeed_logic &logic, uint64_t total
 {
     bool channel_changed = false;
     uint16_t channel_num = 0;
+
     for (const GSList *l = channels; l; l = l->next) {
         sr_channel *const probe = (sr_channel*)l->data;
         assert(probe);
-        if (probe->type == SR_CHANNEL_LOGIC) {
-            channel_num += probe->enabled;
-            if (!channel_changed && probe->enabled) {
+        if (probe->type == SR_CHANNEL_LOGIC && probe->enabled) {
+            channel_num++;
+            if (!channel_changed){
                 channel_changed = !has_data(probe->index);
             }
         }
     }
 
-    if (total_sample_count != _total_sample_count ||
-        channel_num != _channel_num ||
-        channel_changed) {
+    if (total_sample_count != _total_sample_count
+        || channel_num != _channel_num
+        || channel_changed) {
 
         free_data();
-
         _ch_index.clear();
 
         _total_sample_count = total_sample_count;
@@ -194,8 +196,8 @@ void LogicSnapshot::first_payload(const sr_datafeed_logic &logic, uint64_t total
                 _ch_index.push_back(probe->index);
             }
         }
-
-    } else {
+    }
+    else {
         for(auto& iter : _ch_data) {
             for(auto& iter_rn : iter) {
                 iter_rn.tog = 0;
@@ -204,18 +206,15 @@ void LogicSnapshot::first_payload(const sr_datafeed_logic &logic, uint64_t total
         }
     }
 
+    assert(_channel_num < LOGIC_TMP_BUF_MAX_SIZE);
+
     _sample_count = 0;
 
-    _last_sample.clear();
-    _sample_cnt.clear();
-    _block_cnt.clear();
-    _ring_sample_cnt.clear();
-
     for (unsigned int i = 0; i < _channel_num; i++) {
-        _last_sample.push_back(0);
-        _sample_cnt.push_back(0);
-        _block_cnt.push_back(0);
-        _ring_sample_cnt.push_back(0);
+        _last_sample[i] = 0;
+        _sample_cnt[i] = 0;
+        _block_cnt[i] = 0;
+        _ring_sample_cnt[i] = 0;
     }
 
     append_payload(logic);
@@ -224,7 +223,7 @@ void LogicSnapshot::first_payload(const sr_datafeed_logic &logic, uint64_t total
 
 void LogicSnapshot::append_payload(const sr_datafeed_logic &logic)
 {
-   std::lock_guard<std::mutex> lock(_mutex);
+    std::lock_guard<std::mutex> lock(_mutex);
 
     if (logic.format == LA_CROSS_DATA)
         append_cross_payload(logic);
@@ -296,14 +295,6 @@ void LogicSnapshot::append_cross_payload(const sr_datafeed_logic &logic)
             const uint64_t index1 = (_ring_sample_count >> LeafBlockPower) % RootScale;
             const uint64_t offset = (_ring_sample_count % LeafBlockSamples) / Scale;
 
-//            _dest_ptr = (uint64_t *)_ch_data[i][index0].lbp[index1] + offset;
-//            uint64_t mipmap_index = offset / 8 / Scale;
-//            uint64_t mipmap_offset = (offset / 8) % Scale;
-//            uint64_t *l1_mipmap = (uint64_t *)_ch_data[i][index0].lbp[index1] +
-//                                  (LeafBlockSamples / Scale) + mipmap_index;
-//            *l1_mipmap += ((_last_sample[i] ^ *(uint64_t *)_dest_ptr) != 0 ? 1ULL : 0ULL) << mipmap_offset;
-//            _last_sample[i] = *(uint64_t *)_dest_ptr & (1ULL << (Scale - 1)) ? ~0ULL : 0ULL;
-
             _ch_fraction = (_ch_fraction + 1) % _channel_num;
             if (_ch_fraction == 0)
                 _ring_sample_count += Scale;
@@ -393,8 +384,6 @@ void LogicSnapshot::append_split_payload(const sr_datafeed_logic &logic)
 {
     assert(logic.format == LA_SPLIT_DATA);
 
-    _times++;
-
     uint64_t samples = logic.length * 8;
     uint16_t order = logic.order;
     assert(order < _ch_data.size());
@@ -460,8 +449,8 @@ void LogicSnapshot::append_split_payload(const sr_datafeed_logic &logic)
         }
     }
 
-    _sample_count = *min_element(_sample_cnt.begin(), _sample_cnt.end());
-    _ring_sample_count = *min_element(_ring_sample_cnt.begin(), _ring_sample_cnt.end());
+    _sample_count = array::find_min_uint64(_sample_cnt, _channel_num);
+    _ring_sample_count = array::find_min_uint64(_ring_sample_cnt, _channel_num);
 }
 
 void LogicSnapshot::calc_mipmap(unsigned int order, uint8_t index0, uint8_t index1, uint64_t samples)
@@ -1032,16 +1021,15 @@ uint8_t *LogicSnapshot::get_block_buf(int block_index, int sig_index, bool &samp
 int LogicSnapshot::get_ch_order(int sig_index)
 {
     uint16_t order = 0;
-    for (auto& iter:_ch_index) {
-        if (iter == sig_index)
-            break;
-        order++;
+
+    for (uint16_t i : _ch_index) {
+        if (i == sig_index)
+            return order;
+        else
+            order++;
     }
 
-    if (order >= _ch_index.size())
-        return -1;
-    else
-        return order;
+    return -1;
 }
 
 } // namespace data
diff --git a/DSView/pv/data/logicsnapshot.h b/DSView/pv/data/logicsnapshot.h
index 53aeebf7..1e1abdca 100644
--- a/DSView/pv/data/logicsnapshot.h
+++ b/DSView/pv/data/logicsnapshot.h
@@ -32,6 +32,7 @@
 #include <map>
 
 #define CHANNEL_MAX_COUNT 128
+#define LOGIC_TMP_BUF_MAX_SIZE  512
 
 namespace LogicSnapshotTest {
 class Pow2;
@@ -186,18 +187,16 @@ private:
 
 private:
     std::vector<std::vector<struct RootNode>> _ch_data;
-    uint64_t _block_num;
-    uint8_t _byte_fraction;
-    uint16_t _ch_fraction;
-    void *_src_ptr;
-    void *_dest_ptr;
+    uint64_t    _block_num;
+    uint8_t     _byte_fraction;
+    uint16_t    _ch_fraction;
+    void        *_src_ptr;
+    void        *_dest_ptr;
 
-    std::vector<uint64_t> _sample_cnt;
-    std::vector<uint64_t> _block_cnt;
-    std::vector<uint64_t> _ring_sample_cnt;
-    std::vector<uint64_t> _last_sample;
-
-    int _times;
+    uint64_t    _sample_cnt[LOGIC_TMP_BUF_MAX_SIZE];
+    uint64_t    _block_cnt[LOGIC_TMP_BUF_MAX_SIZE];
+    uint64_t    _ring_sample_cnt[LOGIC_TMP_BUF_MAX_SIZE];
+    uint64_t    _last_sample[LOGIC_TMP_BUF_MAX_SIZE];
  
 	friend class LogicSnapshotTest::Pow2;
 	friend class LogicSnapshotTest::Basic;
diff --git a/DSView/pv/data/snapshot.cpp b/DSView/pv/data/snapshot.cpp
index 3321ca29..8558ea5c 100644
--- a/DSView/pv/data/snapshot.cpp
+++ b/DSView/pv/data/snapshot.cpp
@@ -37,10 +37,10 @@ Snapshot::Snapshot(int unit_size, uint64_t total_sample_count, unsigned int chan
     _total_sample_count(total_sample_count),
     _ring_sample_count(0),
     _unit_size(unit_size),
-    _memory_failed(false),
-    _last_ended(true)
+    _memory_failed(false)
 {
     assert(_unit_size > 0);
+    _last_ended = true;
     _unit_bytes = 1;
     _unit_pitch = 0;
     _have_data = false;
@@ -108,7 +108,7 @@ uint64_t Snapshot::ring_end()
 
 void Snapshot::capture_ended()
 {
-    set_last_ended(true);
+    _last_ended = true;
 }
 
 } // namespace data
diff --git a/DSView/pv/data/snapshot.h b/DSView/pv/data/snapshot.h
index dc21fbcf..e2ee9dbc 100644
--- a/DSView/pv/data/snapshot.h
+++ b/DSView/pv/data/snapshot.h
@@ -65,10 +65,6 @@ public:
         return _last_ended;
     }
 
-    inline void set_last_ended(bool ended){
-        _last_ended = ended;
-    }
-
     inline unsigned int get_channel_num(){
         return _channel_num;
     }
diff --git a/DSView/pv/data/spectrumstack.cpp b/DSView/pv/data/spectrumstack.cpp
index e2a41b88..ec634a99 100644
--- a/DSView/pv/data/spectrumstack.cpp
+++ b/DSView/pv/data/spectrumstack.cpp
@@ -183,7 +183,7 @@ void SpectrumStack::calc_fft()
         }
     }
 
-    if (!data)
+    if (data == NULL)
         return;
 
     // Check we have a snapshot of data
diff --git a/DSView/pv/interface/icallbacks.h b/DSView/pv/interface/icallbacks.h
index 3d9b8f55..52a1557c 100644
--- a/DSView/pv/interface/icallbacks.h
+++ b/DSView/pv/interface/icallbacks.h
@@ -46,7 +46,6 @@ public:
     virtual void receive_data_len(quint64 len)=0;
     
     virtual void receive_header()=0;
-    virtual void data_received()=0;
     virtual void trigger_message(int msg)=0;  
 };
 
diff --git a/DSView/pv/mainwindow.cpp b/DSView/pv/mainwindow.cpp
index c4db6b5b..616e864e 100644
--- a/DSView/pv/mainwindow.cpp
+++ b/DSView/pv/mainwindow.cpp
@@ -1390,10 +1390,6 @@ namespace pv
     {
     }
 
-    void MainWindow::data_received()
-    {
-    }
-
     void MainWindow::check_usb_device_speed()
     {
         // USB device speed check
diff --git a/DSView/pv/mainwindow.h b/DSView/pv/mainwindow.h
index cdfb33cb..71d10a67 100644
--- a/DSView/pv/mainwindow.h
+++ b/DSView/pv/mainwindow.h
@@ -161,7 +161,6 @@ private:
     void decode_done();
     void receive_data_len(quint64 len);
     void receive_header();    
-    void data_received();
     void trigger_message(int msg);
     void session_save();
 
diff --git a/DSView/pv/sigsession.cpp b/DSView/pv/sigsession.cpp
index 3b1f55f4..2d398a74 100644
--- a/DSView/pv/sigsession.cpp
+++ b/DSView/pv/sigsession.cpp
@@ -1046,8 +1046,6 @@ namespace pv
 
         receive_data(logic.length * 8 / get_ch_num(SR_CHANNEL_LOGIC));
 
-        _callback->data_received();
-
         _data_updated = true;
     }
 
diff --git a/DSView/pv/sigsession.h b/DSView/pv/sigsession.h
index 9caf6a8d..14435a88 100644
--- a/DSView/pv/sigsession.h
+++ b/DSView/pv/sigsession.h
@@ -130,6 +130,10 @@ public:
         return &_device_agent;
     }
 
+    inline void set_callback(ISessionCallback *callback){
+        _callback = callback;
+    }
+
     bool init();
     void uninit();
     void Open();
@@ -140,8 +144,7 @@ public:
     bool set_file(QString name);
     void close_file(ds_device_handle dev_handle);
     bool start_capture(bool instant);
-    void stop_capture(); 
-	 
+    void stop_capture();	 
     uint64_t cur_samplerate();
     uint64_t cur_snap_samplerate();
 
@@ -152,8 +155,6 @@ public:
     double cur_sampletime();
     double cur_snap_sampletime();
     double cur_view_time();
-    void set_cur_snap_samplerate(uint64_t samplerate);
-    void set_cur_samplelimits(uint64_t samplelimits);
 
     inline void set_session_time(QDateTime time){
          _session_time = time;
@@ -213,7 +214,6 @@ public:
     void data_auto_lock(int lock);
     void data_auto_unlock();
     bool get_data_auto_lock();
-
     void spectrum_rebuild();
     void lissajous_rebuild(bool enable, int xindex, int yindex, double percent);
     void lissajous_disable();
@@ -222,8 +222,6 @@ public:
                       pv::view::DsoSignal *dsoSig2,
                       data::MathStack::MathType type);
 
-    void math_disable();
-
     inline bool trigd(){
         return _trigger_flag;
     }
@@ -292,10 +290,6 @@ public:
         return _is_instant;
     }
 
-    inline void set_callback(ISessionCallback *callback){
-        _callback = callback;
-    }
-
     inline bool is_working(){
         return _is_working;
     }
@@ -374,6 +368,11 @@ public:
     void broadcast_msg(int msg);
     bool switch_work_mode(int mode);
 
+private:
+    void set_cur_samplelimits(uint64_t samplelimits);
+    void set_cur_snap_samplerate(uint64_t samplerate);
+    void math_disable();
+
 private:
     bool exec_capture();
     void exit_capture();
diff --git a/DSView/pv/utility/array.cpp b/DSView/pv/utility/array.cpp
new file mode 100644
index 00000000..87513c37
--- /dev/null
+++ b/DSView/pv/utility/array.cpp
@@ -0,0 +1,60 @@
+/*
+ * This file is part of the DSView project.
+ * DSView is based on PulseView.
+ *
+ * Copyright (C) 2022 DreamSourceLab <support@dreamsourcelab.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 2 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+#include "array.h"
+#include <assert.h>
+
+namespace pv
+{
+    namespace array
+    {
+        uint64_t find_min_uint64(uint64_t *arr, int size)
+        { 
+            assert(arr);
+            assert(size);
+
+            uint64_t *p = arr;            
+            uint64_t v = *p;            
+
+            for (int i=1; i<size; i++){
+                p++;
+                if (*p < v)
+                    v = *p;
+            }
+            return v;
+        }
+
+        uint64_t find_max_uint64(uint64_t *arr, int size)
+        { 
+            assert(arr);
+            assert(size);
+
+            uint64_t *p = arr;            
+            uint64_t v = *p;            
+
+            for (int i=1; i<size; i++){
+                p++;
+                if (*p > v)
+                    v = *p;
+            }
+            return v;
+        }
+    }    
+}
\ No newline at end of file
diff --git a/DSView/pv/utility/array.h b/DSView/pv/utility/array.h
new file mode 100644
index 00000000..681c0624
--- /dev/null
+++ b/DSView/pv/utility/array.h
@@ -0,0 +1,37 @@
+/*
+ * This file is part of the DSView project.
+ * DSView is based on PulseView.
+ *
+ * Copyright (C) 2022 DreamSourceLab <support@dreamsourcelab.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 2 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#ifndef UTILITY_ARRAY_H
+#define UTILITY_ARRAY_H
+
+#include <stdint.h>
+
+namespace pv
+{
+    namespace array
+    {
+        uint64_t find_min_uint64(uint64_t *arr, int size);
+
+        uint64_t find_max_uint64(uint64_t *arr, int size);
+    }    
+}
+
+#endif
\ No newline at end of file
diff --git a/DSView/pv/view/analogsignal.cpp b/DSView/pv/view/analogsignal.cpp
index bcb84301..ac1fd7f9 100644
--- a/DSView/pv/view/analogsignal.cpp
+++ b/DSView/pv/view/analogsignal.cpp
@@ -105,6 +105,8 @@ AnalogSignal::AnalogSignal(view::AnalogSignal *s, pv::data::Analog *data, sr_cha
     _hover_point(QPointF(-1, -1)),
     _hover_value(0)
 {
+    _signal_type = ANALOG_SIGNAL;
+    
     _typeWidth = 5;
     _bits = s->get_bits();
     _ref_min = s->get_ref_min();
diff --git a/DSView/pv/view/logicsignal.cpp b/DSView/pv/view/logicsignal.cpp
index 352ae2be..f6889a35 100644
--- a/DSView/pv/view/logicsignal.cpp
+++ b/DSView/pv/view/logicsignal.cpp
@@ -56,6 +56,7 @@ LogicSignal::LogicSignal(view::LogicSignal *s,
     _data(data),
     _trig(s->get_trig())
 {
+    _signal_type = LOGIC_SIGNAL;
 }
 
 LogicSignal::~LogicSignal()
diff --git a/DSView/pv/view/signal.cpp b/DSView/pv/view/signal.cpp
index 0443f86e..9377e07f 100644
--- a/DSView/pv/view/signal.cpp
+++ b/DSView/pv/view/signal.cpp
@@ -33,16 +33,17 @@ namespace view {
 
 Signal::Signal(sr_channel *probe) :
     Trace(probe->name, probe->index, probe->type),
-    _probe(probe),
-    _signal_type(UNKNOWN_SIGNAL)
-{
+    _probe(probe)
+{   
+    _signal_type = UNKNOWN_SIGNAL;
     session = AppControl::Instance()->GetSession();
 }
 
 Signal::Signal(const Signal &s, sr_channel *probe) :
     Trace((const Trace &)s), 
     _probe(probe)
-{
+{   
+    _signal_type = UNKNOWN_SIGNAL;
     session = AppControl::Instance()->GetSession();
 }
 
diff --git a/DSView/pv/view/signal.h b/DSView/pv/view/signal.h
index 3d071feb..0461259f 100644
--- a/DSView/pv/view/signal.h
+++ b/DSView/pv/view/signal.h
@@ -60,9 +60,6 @@ class Signal : public Trace
 {
     Q_OBJECT
 
-private:
-
-
 protected:
     Signal(sr_channel * const probe);
 
diff --git a/DSView/pv/view/spectrumtrace.cpp b/DSView/pv/view/spectrumtrace.cpp
index 91a26376..a256ddb7 100644
--- a/DSView/pv/view/spectrumtrace.cpp
+++ b/DSView/pv/view/spectrumtrace.cpp
@@ -322,10 +322,6 @@ void SpectrumTrace::paint_mid(QPainter &p, int left, int right, QColor fore, QCo
             _vmin = _vmax - _dbv_range;
         }
 
-        //const double max_value = *std::max_element(dc_ignored ? ++samples.begin() : samples.begin(), samples.end());
-        //const double min_value = *std::min_element(dc_ignored ? ++samples.begin() : samples.begin(), samples.end());
-        //_vmax = (_view_mode == 0) ? max_value : 20*log10(max_value);
-        //_vmin = (_view_mode == 0) ? min_value : 20*log10(min_value);
         const double scale = height / (_vmax - _vmin);
 
         double x = (view_start-view_off)*pixels_per_sample;
diff --git a/DSView/pv/view/view.cpp b/DSView/pv/view/view.cpp
index 975a6ee7..92759344 100644
--- a/DSView/pv/view/view.cpp
+++ b/DSView/pv/view/view.cpp
@@ -489,11 +489,6 @@ void View::set_trig_time()
     _trig_time_setted = true;
 }
 
-bool View::trig_time_setted()
-{
-    return _trig_time_setted;
-}
-
 void View::receive_end()
 {
     if (_device_agent->get_work_mode() == LOGIC) {
diff --git a/DSView/pv/view/view.h b/DSView/pv/view/view.h
index 917fd116..71ab7456 100644
--- a/DSView/pv/view/view.h
+++ b/DSView/pv/view/view.h
@@ -299,7 +299,10 @@ public slots:
 
     // --
     void set_trig_time();
-    bool trig_time_setted();
+
+    inline bool trig_time_setted(){
+        return _trig_time_setted;
+    }
 
     //
     void header_updated();