diff --git a/avr-gcc-toolchain.cmake b/avr-gcc-toolchain.cmake
index 6eb3461..e49f583 100644
--- a/avr-gcc-toolchain.cmake
+++ b/avr-gcc-toolchain.cmake
@@ -14,8 +14,10 @@ set(AVR_MCU attiny13a)
 #set(AVR_MCU attiny404) # this is the avrxmega3 series
 #set(AVR_MCU avr64dd28) # Newer DX series, avrxmega2
 
-set(F_CPU 16000000UL)
+#set(F_CPU 16000000UL)
 #set(F_CPU 8000000)
+set(F_CPU 4800000)
+
 add_compile_definitions(F_CPU=${F_CPU})
 # add_compile_definitions(MCU=atmega328p)
 #add_compile_definitions(__AVR_ATmega328P__)