diff --git a/Makefile b/Makefile
index b9ce4e0..0c2a47b 100644
--- a/Makefile
+++ b/Makefile
@@ -4,9 +4,9 @@
 
 # https://gcc.gnu.org/onlinedocs/gcc/AVR-Options.html
 # avr-gcc -mmcu=atmega328p -print-multi-directory
-MCU = avr5
+# MCU = avr5
 # avr-gcc -mmcu=avr64ea28 -print-multi-directory
-# MCU = avrxmega2
+MCU = avrxmega2
 
 MAIN = libsdc.c
 SRC = 
diff --git a/libsdc.c b/libsdc.c
index 8a7eb0b..132658d 100644
--- a/libsdc.c
+++ b/libsdc.c
@@ -17,7 +17,7 @@
  * @param crc
  */
 static void command(uint8_t command, uint32_t argument, uint8_t crc) {
-    // 6-bit command, start bit is always 0, _sdcTxter bit is 1 (host command)
+    // 6-bit command, start bit is always 0, transmitter bit is 1 (host command)
     _sdcTx(command | 0x40);
 
     _sdcTx(argument >> 24);
diff --git a/libsdc.h b/libsdc.h
index a53b0a4..62cd2b1 100644
--- a/libsdc.h
+++ b/libsdc.h
@@ -119,8 +119,8 @@
 bool sdcReadMultiBlock(uint32_t address, SDConsumer consume);
 
 /**
- * Writes a single block of 512 bytes starting at the given address
- * from the given buffer and returns true on success, false otherwise.
+ * Writes a single block of 512 bytes at the given address from 
+ * the given buffer and returns true on success, false otherwise.
  *
  * @param address address in 512 byte units
  * @param block 512 byte buffer