diff --git a/Makefile b/Makefile
index c49d003..be88002 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 PRG            = rgbyteclock
-OBJ            = rgbyteclock.o timer.o lcd.o main.o rtc.o spi.o ringbuffer.o crc.o led1642gw.o
+OBJ            = rgbyteclock.o timer.o lcd.o main.o rtc.o spi.o ringbuffer.o crc.o ledcontroller.o
 MCU_TARGET     = atmega164a
 OPTIMIZE       = -Os
 
@@ -25,7 +25,7 @@ $(PRG).elf: $(OBJ)
 	@echo
 
 # dependency:
-rgbyteclock.o: timer.o lcd.o rgbyteclock.h rtc.o spi.o led1642gw.o
+rgbyteclock.o: timer.o lcd.o rgbyteclock.h rtc.o spi.o ledcontroller.o
 main.o: rgbyteclock.o lcd.o spi.o led1642gw.o
 timer.o: timer.h
 lcd.o: lcd.h timer.o
@@ -33,7 +33,7 @@ rtc.o: rtc.h
 spi.o: spi.h crc.o ringbuffer.o
 ringbuffer.o: ringbuffer.h
 crc.o: crc.h
-led1642gw.o: led1642gw.h
+ledcontroller.o: ledcontroller.h
 
 clean:
 	rm -rf *.o $(PRG).elf *.eps *.png *.pdf *.bak 
diff --git a/led1642gw.c b/led1642gw.c
deleted file mode 100644
index bfdf031..0000000
--- a/led1642gw.c
+++ /dev/null
@@ -1,18 +0,0 @@
-
-/*
- * ----------------------------------------------------------------------------
- * "THE BEER-WARE LICENSE" (Revision 42):
- * <struppi@struppi.name> wrote this file. As long as you retain this notice you
- * can do whatever you want with this stuff. If we meet some day, and you think
- * this stuff is worth it, you can buy me a beer in return.
- * (c) 2014 Stefan Rupp
- * ----------------------------------------------------------------------------
- */
-
-
-
-void led1642_init(void)
-{
-
-}
-
diff --git a/ledcontroller.c b/ledcontroller.c
new file mode 100644
index 0000000..d1a005c
--- /dev/null
+++ b/ledcontroller.c
@@ -0,0 +1,117 @@
+
+/*
+ * ----------------------------------------------------------------------------
+ * "THE BEER-WARE LICENSE" (Revision 42):
+ * <struppi@struppi.name> wrote this file. As long as you retain this notice you
+ * can do whatever you want with this stuff. If we meet some day, and you think
+ * this stuff is worth it, you can buy me a beer in return.
+ * (c) 2014 Stefan Rupp
+ * ----------------------------------------------------------------------------
+ */
+
+
+#include "ledcontroller.h"
+#include <string.h>
+
+
+#define NUM_LED1642GW_ICs (3)
+#define NUM_LED1642GW_CHANNELS (16)
+#define NUM_CHANNELS (NUM_LED1642GW_CHANNELS*NUM_LED1642GW_ICs)
+
+static uint16_t ledbuffer[NUM_CHANNELS];
+
+static int8_t get_channel_from_lednum(uint8_t lednum, uint8_t *channel_r, uint8_t *channel_g, uint8_t *channel_b)
+{
+  uint8_t ret;
+
+  if (lednum < 15) {
+    *channel_r = 3*lednum;
+    *channel_g = 3*lednum+1;
+    *channel_b = 3*lednum+2;
+    if ( lednum >= 10 ) {
+      *channel_r += 2;
+      *channel_g += 2;
+      *channel_b += 2;
+    }
+    else if ( lednum >= 5 ) {
+      *channel_r += 1;
+      *channel_g += 1;
+      *channel_b += 1;
+    }
+    ret = 1;
+  }
+  else {
+    ret = 0;
+  }
+
+  return ret;
+}
+
+static void write_data(uint16_t data, uint8_t le_clocks)
+{
+  PORTC &= ~(1<<PC3);
+  PORTC &= ~(1<<PC2);
+  uint16_t mask = 0x8000;
+  int8_t bit;
+  for (bit=15; bit>=le_clocks; bit--) {
+    if(data&mask) { PORTC |= (1<<PC4); }
+    else { PORTC &= ~(1<<PC4); }
+    PORTC |= (1<<PC3);
+    PORTC &= ~(1<<PC3);
+    mask >>= 1;
+  }
+  PORTC |= (1<<PC2);
+  for (/*noting to initialize*/; bit>=0; bit--) {
+    if(data&mask) { PORTC |= (1<<PC4); }
+    else { PORTC &= ~(1<<PC4); }
+    PORTC |= (1<<PC3);
+    PORTC &= ~(1<<PC3);
+    mask >>= 1;
+  }
+}
+
+static void write_data_latch(uint16_t data)
+{
+  write_data(data, 4);
+}
+
+static void write_global_latch(uint16_t data)
+{
+  write_data(data, 6);
+}
+
+
+void ledcontroller_init(void)
+{
+
+  DDRC |= (1<<PC3); // SCK
+  DDRC |= (1<<PC4); // DATA
+  DDRC |= (1<<PC2); // LE
+  PORTC |= (1<<PC3); // SCK
+  PORTC |= (1<<PC4); // DATA
+  PORTC |= (1<<PC2); // LE
+  memset(ledbuffer, 0x00, sizeof(ledbuffer));
+  led_flush();
+}
+
+
+void led_set(uint8_t lednum, uint16_t red, uint16_t green, uint16_t blue)
+{
+  uint8_t c_r, c_g, c_b;
+  
+  if ( get_channel_from_lednum(lednum, &c_r, &c_g, &c_b) > 0 ) {
+    ledbuffer[c_r] = red;
+    ledbuffer[c_g] = green;
+    ledbuffer[c_b] = blue;
+  }
+}
+
+
+void led_flush(void)
+{
+  for (uint8_t i=0; i<NUM_CHANNELS-1; i++) {
+    write_data_latch(ledbuffer[i]);
+  }
+  write_global_latch(ledbuffer[NUM_CHANNELS-1]);
+}
+
diff --git a/led1642gw.h b/ledcontroller.h
similarity index 67%
rename from led1642gw.h
rename to ledcontroller.h
index 68e8c6f..e7f6eb1 100644
--- a/led1642gw.h
+++ b/ledcontroller.h
@@ -9,17 +9,19 @@
  * ----------------------------------------------------------------------------
  */
 
-#ifndef LED1642GW_H
-#define LED1642GW_H
+
+#ifndef LEDCONTROLLER_H
+#define LEDCONTROLLER_H
 
 #include <avr/io.h>
+#include <compat/ina90.h>    // ==> _NOP()
 #include "timer.h"
-#include <util/delay.h>
 
 
-void led1642_init(void);
+void ledcontroller_init(void);
+void led_set(uint8_t lednum, uint16_t red, uint16_t green, uint16_t blue);
+void led_flush(void);
 
 
-
-#endif //LED1642GW_H
+#endif // LEDCONTROLLER_H
 
diff --git a/main.c b/main.c
index 226e855..5f63140 100644
--- a/main.c
+++ b/main.c
@@ -14,12 +14,14 @@
 #include "lcd.h"
 #include "rgbyteclock.h"
 #include "spi.h"
+#include "ledcontroller.h"
 
 int main(void)
 {
   
   timer_init();
   spi_slave_init();
+  ledcontroller_init();
   lcd_init();
 
   rgbyteclock();