--- a/src/AvrAtmel.C
+++ b/src/AvrAtmel.C
@@ -185,7 +185,7 @@
 
 void TAvrAtmel::SetAddress(TAddr addr){
   apc_address = addr;
-  TByte setAddr [3] = { 'A', (addr>>8)&0xff, addr&0xff};
+  TByte setAddr [3] = { 'A', static_cast<TByte>((addr>>8)&0xff), static_cast<TByte>(addr&0xff)};
   Send(setAddr, 3, 1);
   CheckResponse(setAddr [0]);
 }
@@ -294,7 +294,7 @@
       if (flush_buffer){WriteProgramMemoryPage();}
     }
     
-    TByte wrF [2] = { (addr&1)?'C':'c', byte };
+    TByte wrF [2] = { static_cast<TByte>((addr&1)?'C':'c'), byte };
     
     if (apc_address!=(addr>>1) || apc_autoinc==false) SetAddress (addr>>1);
     if (wrF[0]=='C') apc_address++;
@@ -346,7 +346,7 @@
  */
 void TAvrAtmel::WriteOldFuseBits (TByte val)
 {
-  TByte buf[5] = {'.', 0xac, (val & 0x1f) | 0xa0, 0x00, 0xd2 };
+  TByte buf[5] = {'.', 0xac, static_cast<TByte>((val & 0x1f) | 0xa0), 0x00, 0xd2 };
   Info (2, "Write fuse high bits: %02x\n", (int)val);
   Send (buf, 5, 2);
   CheckResponse (buf[1]);
@@ -423,7 +423,7 @@
 }
 
 void TAvrAtmel::WriteLockBits(TByte bits){
-  TByte lockTarget [2] = { 'l', 0xF9 | ((bits << 1) & 0x06) };
+  TByte lockTarget [2] = { 'l', static_cast<TByte>(0xF9 | ((bits << 1) & 0x06)) };
   Send (lockTarget, 2, 1);
   CheckResponse(lockTarget [0]);
   Info(1, "Writing lock bits ...\nReinitializing device\n");
--- a/src/AvrDummy.C
+++ b/src/AvrDummy.C
@@ -81,12 +81,12 @@
 TAvrDummy::GetPartInfo(TAddr addr)
 {
   if (at89) {
-    TByte info [4] = { 0x28, addr & 0x1f, 0, 0 };
+    TByte info [4] = { 0x28, static_cast<TByte>(addr & 0x1f), 0, 0 };
     Send(info, 4);
     return info[3];
   }
 
-  TByte info [4] = { 0x30, 0, addr, 0 };
+  TByte info [4] = { 0x30, 0, static_cast<TByte>(addr), 0 };
   Send(info, 4);
   return info[3];
 }
@@ -289,7 +289,7 @@
 void
 TAvrDummy::WriteOldFuseBits(TByte val)
 {
-  TByte oldfuse[4] = { 0xAC, (val & 0x1F) | 0xA0, 0, 0xD2 };
+  TByte oldfuse[4] = { 0xAC, static_cast<TByte>((val & 0x1F) | 0xA0), 0, 0xD2 };
   Send(oldfuse, 4);
 }
 
@@ -533,7 +533,7 @@
 {
   /* This handles both old (byte 2, bits 1-2)
      and new (byte 4, bits 0-5) devices.  */
-  TByte lock[4] = { 0xAC, 0xF9 | ((bits << 1) & 0x06), 0xFF, bits };
+  TByte lock[4] = { 0xAC, static_cast<TByte>(0xF9 | ((bits << 1) & 0x06)), 0xFF, bits };
   TByte rbits;
 
   if (at89)
--- a/src/Stk500.C
+++ b/src/Stk500.C
@@ -518,7 +518,7 @@
 
 TByte TStk500::ReadCalFuseBits(int addr)
 {
-  TByte cmd[] = { 0x38, 0x00, addr, 0x00 };
+  TByte cmd[] = { 0x38, 0x00, static_cast<TByte>(addr), 0x00 };
 
   return UniversalCmd(cmd);
 }