diff --git a/src/energenie/drv/gpio_arduino.c b/src/energenie/drv/gpio_arduino.c
index ac0a6de..f1f9bea 100644
--- a/src/energenie/drv/gpio_arduino.c
+++ b/src/energenie/drv/gpio_arduino.c
@@ -5,7 +5,8 @@
  * Arduino internally uses the 'wiring' library, but experiments have shown
  * that it is really slow.
  *
- * (see blog by skpang)
+ * See 'Faster IO on the Arduino' on the SKPang blog:
+ * http://skpang.co.uk/blog/archives/323
  *
  * So this module uses direct register writes, and provides a placeholder for
  * compile-time selection of bitmasks and bitpatterns to support more Arduino
@@ -72,17 +73,16 @@
 
 /****** MACROS *****/
 
-//#define INP_GPIO(g) *(gpio+((g)/10)) &= ~(7<<(((g)%10)*3))
-//#define OUT_GPIO(g) *(gpio+((g)/10)) |=  (1<<(((g)%10)*3))
-//#define SET_GPIO_ALT(g,a) *(gpio+(((g)/10))) |= (((a)<=3?(a)+4:(a)==4?3:2)<<(((g)%10)*3))
+//#define INP_GPIO(g)
+//#define OUT_GPIO(g)
 
-//#define GPIO_SET *(gpio+7)  // sets   bits which are 1 ignores bits which are 0
-//#define GPIO_CLR *(gpio+10) // clears bits which are 1 ignores bits which are 0
+//#define GPIO_SET
+//#define GPIO_CLR
 
-//#define GPIO_READ(g) ((*(gpio+13)&(1<<g)) != 0)
+//#define GPIO_READ(g)
 
-//#define GPIO_HIGH(g) GPIO_SET = (1<<(g))
-//#define GPIO_LOW(g)  GPIO_CLR = (1<<(g))
+//#define GPIO_HIGH(g)
+//#define GPIO_LOW(g)
 
 
 void gpio_init()
diff --git a/src/energenie/drv/hrf69_test.c b/src/energenie/drv/hrf69_test.c
index f7a97a1..a0d3b39 100644
--- a/src/energenie/drv/hrf69_test.c
+++ b/src/energenie/drv/hrf69_test.c
@@ -40,7 +40,6 @@
 void hrf_test_send_ook(void);
 
 
-
 #if defined(HRF69_TEST)
 int main(int argc, char **argv)
 {
diff --git a/src/energenie/drv/spis_arduino.c b/src/energenie/drv/spis_arduino.c
deleted file mode 100644
index bd41ac0..0000000
--- a/src/energenie/drv/spis_arduino.c
+++ /dev/null
@@ -1,6 +0,0 @@
-// placeholder for arduino SPI software driver
-//
-// This will be used to aid porting to the arduino.
-// The arduino has more predictable timing than the Raspberry Pi,
-// and thus it is a much better test suite platform.
-