diff --git a/avr-gcc-toolchain.cmake b/avr-gcc-toolchain.cmake
index 845b877..24f7aee 100644
--- a/avr-gcc-toolchain.cmake
+++ b/avr-gcc-toolchain.cmake
@@ -9,17 +9,18 @@ set(CMAKE_SYSTEM_PROCESSOR avr)
 
 # Specify the compiler and linker
 #set(AVR_MCU atmega328p) # The old Classic
+set(AVR_MCU attiny13a)
 #set(AVR_MCU attiny85) # The older ATtiny series, avr25
-set(AVR_MCU attiny404) # this is the avrxmega3 series
+#set(AVR_MCU attiny404) # this is the avrxmega3 series
 #set(AVR_MCU avr64dd28) # Newer DX series, avrxmega2
 
-# The default frequency of an 328p devboard using the external crystal.
 set(F_CPU 16000000UL)
 #set(F_CPU 8000000)
 add_compile_definitions(F_CPU=${F_CPU})
 # add_compile_definitions(MCU=atmega328p)
 #add_compile_definitions(__AVR_ATmega328P__)
-add_compile_definitions(__AVR_ATtiny404__)
+#add_compile_definitions(__AVR_ATtiny404__)
+add_compile_definitions(__AVR_ATtiny13a__)
 
 # Set up the programmer for it
 #set(PROGRAMMER usbasp-clone)