diff --git a/sis8300bcmApp/Db/sis8300bcm-acct.template b/sis8300bcmApp/Db/sis8300bcm-acct.template
index 439d68191ed755f5148a802a0224ff9399223602..303c3c87ad69f1b151a32fa54f488045d1fe2ed0 100644
--- a/sis8300bcmApp/Db/sis8300bcm-acct.template
+++ b/sis8300bcmApp/Db/sis8300bcm-acct.template
@@ -1201,6 +1201,48 @@ record(ai, "$(P)$(R)TriggerWidthR")
     field(SCAN, "I/O Intr")
 }
 
+record(ao, "$(P)$(R)AutoFlatTopStart")
+{
+    field(DTYP, "asynFloat64")
+    field(OUT,  "@asyn($(PORT),$(ADDR=0),$(TIMEOUT=1))BCM.ACCT.AUTO_FLATTOP_START")
+    field(EGU,  "ns")
+    field(PREC, "4")
+    field(VAL,  "0.0")
+    field(PINI, "YES")
+    field(ASG,  "critical")
+    info(autosaveFields, "VAL")
+}
+
+record(ai, "$(P)$(R)AutoFlatTopStartR")
+{
+    field(DTYP, "asynFloat64")
+    field(INP,  "@asyn($(PORT),$(ADDR=0),$(TIMEOUT=1))BCM.ACCT.AUTO_FLATTOP_START")
+    field(EGU,  "ns")
+    field(PREC, "4")
+    field(SCAN, "I/O Intr")
+}
+
+record(ao, "$(P)$(R)AutoFlatTopEnd")
+{
+    field(DTYP, "asynFloat64")
+    field(OUT,  "@asyn($(PORT),$(ADDR=0),$(TIMEOUT=1))BCM.ACCT.AUTO_FLATTOP_END")
+    field(EGU,  "ns")
+    field(PREC, "4")
+    field(VAL,  "0.0")
+    field(PINI, "YES")
+    field(ASG,  "critical")
+    info(autosaveFields, "VAL")
+}
+
+record(ai, "$(P)$(R)AutoFlatTopEndR")
+{
+    field(DTYP, "asynFloat64")
+    field(INP,  "@asyn($(PORT),$(ADDR=0),$(TIMEOUT=1))BCM.ACCT.AUTO_FLATTOP_END")
+    field(EGU,  "ns")
+    field(PREC, "4")
+    field(SCAN, "I/O Intr")
+}
+
 record(ai, "$(P)$(R)LICoefficientR")
 {
     field(DTYP, "asynFloat64")
diff --git a/sis8300bcmApp/src/sis8300bcm.cpp b/sis8300bcmApp/src/sis8300bcm.cpp
index a88da54adfb6b14ca70ca4861292999da09b016a..d5bd1e6d4ffd4d0a79f6401a602117a5409490ee 100644
--- a/sis8300bcmApp/src/sis8300bcm.cpp
+++ b/sis8300bcmApp/src/sis8300bcm.cpp
@@ -271,6 +271,8 @@ sis8300bcm::sis8300bcm(const char *portName, const char *devicePath,
     createParam(BCMAcctLeakyCoefficientString,              asynParamFloat64,   &BCMAcctLeakyCoefficient);
     createParam(BCMAcctLeakyThresholdString,                asynParamFloat64,   &BCMAcctLeakyThreshold);
     createParam(BCMAcctTriggerWidthString,                  asynParamFloat64,   &BCMAcctTriggerWidth);
+    createParam(BCMAcctAutoFlatTopStartString,              asynParamFloat64,   &BCMAcctAutoFlatTopStart);
+    createParam(BCMAcctAutoFlatTopEndString,                asynParamFloat64,   &BCMAcctAutoFlatTopEnd);
     // DIFF block, channel specific
     createParam(BCMDiffSourceAString,                       asynParamInt32,     &BCMDiffSourceA);
     createParam(BCMDiffSourceBString,                       asynParamInt32,     &BCMDiffSourceB);
@@ -928,7 +930,18 @@ int sis8300bcm::readbackParameters()
             return ret;
         }
         setDoubleParam(addr, BCMAcctTriggerWidth, doubleValue);
-
+        ret = sis8300drvbcm_get_channel_auto_flattop_start(mDeviceHandle, addr, &doubleValue);
+        if (ret) {
+            asynPrintError(pasynUserSelf, "sis8300drvbcm_get_channel_auto_flattop_start returned %d", ret);
+            return ret;
+        }
+        setDoubleParam(addr, BCMAcctAutoFlatTopStart, doubleValue);
+        ret = sis8300drvbcm_get_channel_auto_flattop_end(mDeviceHandle, addr, &doubleValue);
+        if (ret) {
+            asynPrintError(pasynUserSelf, "sis8300drvbcm_get_channel_auto_flattop_end returned %d", ret);
+            return ret;
+        }
+        setDoubleParam(addr, BCMAcctAutoFlatTopEnd, doubleValue);
         ret = sis8300drvbcm_get_channel_droop_rate(mDeviceHandle, addr, &doubleValue);
         if (ret) {
             asynPrintError(pasynUserSelf, "sis8300drvbcm_get_channel_droop_rate returned %d", ret);
@@ -2161,6 +2174,16 @@ asynStatus sis8300bcm::writeFloat64(asynUser *pasynUser, epicsFloat64 value)
         if (ret) {
             asynPrintError(pasynUser, "sis8300drvbcm_set_pulse_width_filter returned %d", ret);
         }
+    } else if (function == BCMAcctAutoFlatTopStart) {
+        ret = sis8300drvbcm_set_channel_auto_flattop_start(mDeviceHandle, addr, value);
+        if (ret) {
+            asynPrintError(pasynUser, "sis8300drvbcm_set_channel_auto_flattop_start returned %d", ret);
+        }
+    } else if (function == BCMAcctAutoFlatTopEnd) {
+        ret = sis8300drvbcm_set_channel_auto_flattop_end(mDeviceHandle, addr, value);
+        if (ret) {
+            asynPrintError(pasynUser, "sis8300drvbcm_set_channel_auto_flattop_end returned %d", ret);
+        }
     } else {
         if (function < BCM_FIRST_PARAM) {
             status = sis8300::writeFloat64(pasynUser, value);
diff --git a/sis8300bcmApp/src/sis8300bcm.h b/sis8300bcmApp/src/sis8300bcm.h
index a94570cc8dc98116e94d0b8a73982eb6ec7c681d..48ba603051c9acf3bc8dd8d121d1ee4bb0bb0ce3 100644
--- a/sis8300bcmApp/src/sis8300bcm.h
+++ b/sis8300bcmApp/src/sis8300bcm.h
@@ -167,6 +167,8 @@
 #define BCMAcctLeakyCoefficientString                "BCM.ACCT.LEAKY_INTEGRATOR_COEFFICIENT"
 #define BCMAcctLeakyThresholdString                  "BCM.ACCT.LEAKY_INTEGRATOR_THRESHOLD"
 #define BCMAcctTriggerWidthString                    "BCM.ACCT.TRIGGER_WIDTH"
+#define BCMAcctAutoFlatTopStartString                "BCM.ACCT.AUTO_FLATTOP_START"
+#define BCMAcctAutoFlatTopEndString                  "BCM.ACCT.AUTO_FLATTOP_END"
 // DIFF block, channel specific
 #define BCMDiffSourceAString                         "BCM.DIFF.SOURCE_A"
 #define BCMDiffSourceBString                         "BCM.DIFF.SOURCE_B"
@@ -387,6 +389,8 @@ protected:
     int BCMAcctLeakyCoefficient;
     int BCMAcctLeakyThreshold;
     int BCMAcctTriggerWidth;
+    int BCMAcctAutoFlatTopStart;
+    int BCMAcctAutoFlatTopEnd;
     // DIFF block, channel specific
     int BCMDiffSourceA;
     int BCMDiffSourceB;
diff --git a/vendor/ess/lib/sis8300bcm_reg.h b/vendor/ess/lib/sis8300bcm_reg.h
index b8b18aaf21a821fc8abe0bf9c2e83b986bc6f2ca..1a30b775b5556996731e0bd266fd4afae43feb18 100644
--- a/vendor/ess/lib/sis8300bcm_reg.h
+++ b/vendor/ess/lib/sis8300bcm_reg.h
@@ -148,6 +148,8 @@ extern "C" {
 #define SIS8300BCM_ACCT_X_FLATTOP_FALLING_OFF           0x030
 #define SIS8300BCM_ACCT_X_BEAM_ABOVE_THRESHOLD_REG      0x034
 #define SIS8300BCM_ACCT_X_TRIGGER_WIDTH_OFF             0x035
+#define SIS8300BCM_ACCT_X_AUTO_FLATTOP_RISING_OFF       0x036
+#define SIS8300BCM_ACCT_X_AUTO_FLATTOP_FALLING_OFF      0x037
 
 /*
  DIFF block registers
diff --git a/vendor/ess/lib/sis8300drvbcm.c b/vendor/ess/lib/sis8300drvbcm.c
index b20f85484b82a55f96e7bcd653af197640d09d22..419c5871c503db546ace49916ef1114f3c94ed45 100644
--- a/vendor/ess/lib/sis8300drvbcm.c
+++ b/vendor/ess/lib/sis8300drvbcm.c
@@ -2809,6 +2809,66 @@ int sis8300drvbcm_get_channel_trigger_width(sis8300drv_usr *sisuser, unsigned in
     return ret;
 }
 
+// used to control auto flat top start
+int sis8300drvbcm_set_channel_auto_flattop_start(sis8300drv_usr *sisuser, unsigned int channel, double start)
+{
+    unsigned int reg = SIS8300BCM_CHANNEL_BLOCK_BASE + \
+            (SIS8300BCM_CHANNEL_BLOCK_SIZE * channel) + \
+            SIS8300BCM_ACCT_BANK_OFF + \
+            SIS8300BCM_ACCT_X_AUTO_FLATTOP_RISING_OFF;
+    // register has lowest 13 bits defined
+    int value = (int)(start / 1000000000.0 * s_sampling_frequency);
+    // do not mask off higher bits because value is signed value!
+    int ret = sis8300drv_reg_write(sisuser, reg, (unsigned)value);
+    return ret;
+}
+int sis8300drvbcm_get_channel_auto_flattop_start(sis8300drv_usr *sisuser, unsigned int channel, double *start)
+{
+    unsigned int reg = SIS8300BCM_CHANNEL_BLOCK_BASE + \
+            (SIS8300BCM_CHANNEL_BLOCK_SIZE * channel) + \
+            SIS8300BCM_ACCT_BANK_OFF + \
+            SIS8300BCM_ACCT_X_AUTO_FLATTOP_RISING_OFF;
+    // register has lowest 13 bits defined
+    int value;
+    int ret = sis8300drv_reg_read(sisuser, reg, (unsigned *)&value);
+    if (ret) {
+        return ret;
+    }
+    // do not mask off higher bits because value is signed value!
+    *start = (double)value * 1000000000.0 / s_sampling_frequency;
+    return ret;
+}
+
+// used to control auto flat top end 
+int sis8300drvbcm_set_channel_auto_flattop_end(sis8300drv_usr *sisuser, unsigned int channel, double end)
+{
+    unsigned int reg = SIS8300BCM_CHANNEL_BLOCK_BASE + \
+            (SIS8300BCM_CHANNEL_BLOCK_SIZE * channel) + \
+            SIS8300BCM_ACCT_BANK_OFF + \
+            SIS8300BCM_ACCT_X_AUTO_FLATTOP_FALLING_OFF;
+    // register has lowest 13 bits defined
+    int value = (int)(end / 1000000000.0 * s_sampling_frequency);
+    // do not mask off higher bits because value is signed value!
+    int ret = sis8300drv_reg_write(sisuser, reg, (unsigned)value);
+    return ret;
+}
+int sis8300drvbcm_get_channel_auto_flattop_end(sis8300drv_usr *sisuser, unsigned int channel, double *end)
+{
+    unsigned int reg = SIS8300BCM_CHANNEL_BLOCK_BASE + \
+            (SIS8300BCM_CHANNEL_BLOCK_SIZE * channel) + \
+            SIS8300BCM_ACCT_BANK_OFF + \
+            SIS8300BCM_ACCT_X_AUTO_FLATTOP_FALLING_OFF;
+    // register has lowest 13 bits defined
+    int value;
+    int ret = sis8300drv_reg_read(sisuser, reg, (unsigned *)&value);
+    if (ret) {
+        return ret;
+    }
+    // do not mask off higher bits because value is signed value!
+    *end = (double)value * 1000000000.0 / s_sampling_frequency;
+    return ret;
+}
+
 // used to control fiber out data select
 int sis8300drvbcm_set_fiber_out_data_select(sis8300drv_usr *sisuser, unsigned int channel, unsigned int selection)
 {
diff --git a/vendor/ess/lib/sis8300drvbcm.h b/vendor/ess/lib/sis8300drvbcm.h
index d2f06387486a4e4d23cee7836b635a8be8d7a2cc..9e7e84a9d8af8b539de330b2096b9f029dda30dd 100644
--- a/vendor/ess/lib/sis8300drvbcm.h
+++ b/vendor/ess/lib/sis8300drvbcm.h
@@ -214,6 +214,10 @@ int sis8300drvbcm_get_channel_errant_window_end(sis8300drv_usr *sisuser, unsigne
 int sis8300drvbcm_set_channel_beam_above_threshold(sis8300drv_usr *sisuser, unsigned int channel, double threshold);
 int sis8300drvbcm_get_channel_beam_above_threshold(sis8300drv_usr *sisuser, unsigned int channel, double *threshold);
 int sis8300drvbcm_get_channel_trigger_width(sis8300drv_usr *sisuser, unsigned int channel, double *width);
+int sis8300drvbcm_set_channel_auto_flattop_start(sis8300drv_usr *sisuser, unsigned int channel, double start);
+int sis8300drvbcm_get_channel_auto_flattop_start(sis8300drv_usr *sisuser, unsigned int channel, double *start);
+int sis8300drvbcm_set_channel_auto_flattop_end(sis8300drv_usr *sisuser, unsigned int channel, double end);
+int sis8300drvbcm_get_channel_auto_flattop_end(sis8300drv_usr *sisuser, unsigned int channel, double *end);
 int sis8300drvbcm_set_channel_leaky_coefficient(sis8300drv_usr *sisuser, unsigned int channel, double coefficient);
 int sis8300drvbcm_get_channel_leaky_coefficient(sis8300drv_usr *sisuser, unsigned int channel, double *coefficient);
 int sis8300drvbcm_set_channel_leaky_threshold(sis8300drv_usr *sisuser, unsigned int channel, double threshold);