diff --git a/adc_drv.c b/adc_drv.c
index 6d9d50b..c77c51e 100644
--- a/adc_drv.c
+++ b/adc_drv.c
@@ -4,7 +4,8 @@
 extern adc_drv_if_t ads8691;
 static adc_drv_if_t *p_inst = &ads8691;
 #else
-static adc_drv_if_t *p_inst = NULL;
+#include "builtin_saadc.h"
+static const adc_drv_if_t *p_inst = &builtin_saadc;
 #endif
 
 int adc_init(void)
diff --git a/bmd380_peripheral-Debug.vgdbsettings b/bmd380_peripheral-Debug.vgdbsettings
index be17c3c..206b6d0 100644
--- a/bmd380_peripheral-Debug.vgdbsettings
+++ b/bmd380_peripheral-Debug.vgdbsettings
@@ -111,11 +111,12 @@
       <MaxBreakpointLimit>0</MaxBreakpointLimit>
       <EnableVerboseMode>true</EnableVerboseMode>
       <EnablePrettyPrinters>false</EnablePrettyPrinters>
+      <EnableAbsolutePathReporting>true</EnableAbsolutePathReporting>
     </AdditionalGDBSettings>
     <DebugMethod>
       <ID>jlink-jtag</ID>
       <InterfaceID>com.sysprogs.debug.jlink.jlinksw</InterfaceID>
-      <InterfaceSerialNumber>000682409936</InterfaceSerialNumber>
+      <InterfaceSerialNumber>000682238881</InterfaceSerialNumber>
       <Configuration xsi:type="com.visualgdb.edp.segger.settings">
         <CommandLine>-select USB -device $$SYS:MCU_ID$$ -speed auto -if SWD</CommandLine>
         <ProgramMode>Enabled</ProgramMode>
@@ -140,9 +141,17 @@
     <EnableVirtualHalts>false</EnableVirtualHalts>
     <DynamicAnalysisSettings />
     <EndOfStackSymbol>_estack</EndOfStackSymbol>
-    <TimestampProviderTicksPerSecond>0</TimestampProviderTicksPerSecond>
+    <TimestampProvider>com.sysprogs.arm.dwt</TimestampProvider>
+    <TimestampProviderTicksPerSecond>64000000</TimestampProviderTicksPerSecond>
     <KeepConsoleAfterExit>false</KeepConsoleAfterExit>
     <UnusedStackFillPattern xsi:nil="true" />
+    <RelatedExecutables>
+      <RelatedExecutable>
+        <Program>false</Program>
+        <LoadSymbols>false</LoadSymbols>
+        <ShowInLiveWatch>false</ShowInLiveWatch>
+      </RelatedExecutable>
+    </RelatedExecutables>
     <CheckInterfaceDrivers>true</CheckInterfaceDrivers>
   </Debug>
 </VisualGDBProjectSettings2>
\ No newline at end of file
diff --git a/bmd380_peripheral.vcxproj b/bmd380_peripheral.vcxproj
index 2242d15..a1445e5 100644
--- a/bmd380_peripheral.vcxproj
+++ b/bmd380_peripheral.vcxproj
@@ -201,6 +201,7 @@
     <ClCompile Include="le_gatt.c" />
     <ClCompile Include="le_srv.c" />
     <ClCompile Include="main.c" />
+    <ClCompile Include="builtin_saadc.c.c" />
     <ClCompile Include="sw_drv.c" />
     <ClCompile Include="syscalls.c" />
     <None Include="nRF52811_XXAA_s140.lds" />
@@ -363,6 +364,7 @@
     <ClInclude Include="elite_pin_ctrl.h" />
     <ClInclude Include="FreeRTOSConfig.h" />
     <ClInclude Include="elite_def.h" />
+    <ClInclude Include="builtin_saadc.h" />
     <ClInclude Include="led_drv.h" />
     <ClInclude Include="led_drv_if.h" />
     <ClInclude Include="max5136.h" />
diff --git a/builtin_saadc.c.c b/builtin_saadc.c.c
new file mode 100644
index 0000000..25c69da
--- /dev/null
+++ b/builtin_saadc.c.c
@@ -0,0 +1,82 @@
+#include "builtin_saadc.h"
+#include "nrf_saadc.h"
+
+static uint32_t m_gain = NRF_SAADC_GAIN1_6;
+
+static int init(void)
+{
+    NRF_SAADC->ENABLE     = 0;
+    NRF_SAADC->TASKS_STOP = 1;
+    NRF_SAADC->RESOLUTION = SAADC_RESOLUTION_VAL_14bit;
+    NRF_SAADC->OVERSAMPLE = NRF_SAADC_OVERSAMPLE_4X;
+    return 0;
+}
+
+static int reset(void)
+{
+    // Do nothing...
+    return 0;
+}
+
+static int read(uint32_t channel, int32_t *adc_val)
+{
+    NRF_SAADC->TASKS_STOP  = 1;
+    NRF_SAADC->ENABLE      = 0;
+    NRF_SAADC->CH[0].PSELP = NRF_SAADC_INPUT_AIN0 + channel;
+    NRF_SAADC->CH[0].PSELN = NRF_SAADC_INPUT_DISABLED;
+    NRF_SAADC->CH[0].CONFIG =
+        (NRF_SAADC_RESISTOR_DISABLED << SAADC_CH_CONFIG_RESP_Pos) |
+        (NRF_SAADC_RESISTOR_DISABLED << SAADC_CH_CONFIG_RESN_Pos) |
+        (m_gain << SAADC_CH_CONFIG_GAIN_Pos) |
+        (NRF_SAADC_REFERENCE_INTERNAL << SAADC_CH_CONFIG_REFSEL_Pos) |
+        (NRF_SAADC_ACQTIME_40US << SAADC_CH_CONFIG_TACQ_Pos) |
+        (NRF_SAADC_MODE_SINGLE_ENDED << SAADC_CH_CONFIG_MODE_Pos) |
+        (NRF_SAADC_BURST_ENABLED << SAADC_CH_CONFIG_BURST_Pos);
+    NRF_SAADC->ENABLE = 1;
+
+    uint16_t val                 = 0;
+    NRF_SAADC->RESULT.PTR        = (uint32_t)&val;
+    NRF_SAADC->RESULT.MAXCNT     = 1;
+    NRF_SAADC->EVENTS_RESULTDONE = 0;
+    NRF_SAADC->TASKS_START       = 1;
+    NRF_SAADC->TASKS_SAMPLE      = 1;
+    do {
+    } while (NRF_SAADC->EVENTS_RESULTDONE == 0);
+    *adc_val = val;
+    return 0;
+}
+
+static int gain(adc_gain_t gain)
+{
+    int ret;
+    switch (gain)
+    {
+        case P_GAIN_3P000:
+            m_gain = SAADC_CH_CONFIG_GAIN_Gain1_2;
+            ret    = 0;
+            break;
+        case P_GAIN_1P500:
+            m_gain = SAADC_CH_CONFIG_GAIN_Gain1_4;
+            ret    = 0;
+            break;
+        case P_GAIN_2P500:
+        case P_GAIN_1P250:
+        case NP_GAIN_3P000:
+        case NP_GAIN_2P500:
+        case NP_GAIN_1P500:
+        case NP_GAIN_1P250:
+        case NP_GAIN_0P625:
+        default:
+            m_gain = SAADC_CH_CONFIG_GAIN_Gain1_6;
+            ret    = -1;
+            break;
+    }
+    return ret;
+}
+
+const adc_drv_if_t builtin_saadc = {
+    .init  = init,
+    .reset = reset,
+    .read  = read,
+    .gain  = gain
+};
diff --git a/builtin_saadc.h b/builtin_saadc.h
new file mode 100644
index 0000000..7c8d354
--- /dev/null
+++ b/builtin_saadc.h
@@ -0,0 +1,9 @@
+#pragma once
+#ifndef __BUILTIN_SAADC_H__
+#define  __BUILTIN_SAADC_H__
+
+#include "adc_drv_if.h"
+
+extern const adc_drv_if_t builtin_saadc;
+
+#endif // !__BUILTIN_SAADC_H__