diff --git a/cpu/cc2430/8051def.h b/cpu/cc2430/8051def.h
index ce6bc3357..fe82ce9de 100644
--- a/cpu/cc2430/8051def.h
+++ b/cpu/cc2430/8051def.h
@@ -51,6 +51,26 @@
 #define CC_NON_BANKED
 #endif
 
+/*
+ * Max Stack Depth manipulation. It is possible to get up to 247 bytes
+ * allocated for the stack if:
+ * - You set this to 1 and
+ * - You have a patched toolchain and
+ * - You don't use __bit variables
+ * - You do not link libraries using BIT registers (e.g. printf_large)
+ * Enabling this will mean ISRs will NOT push bits (#pragma exclude bits) so
+ * make sure you know what you're doing
+ *
+ * More information on the wiki
+ */
+#define CC_CONF_OPTIMIZE_STACK_SIZE 0
+
+#if CC_CONF_OPTIMIZE_STACK_SIZE
+#define CC_AT_DATA
+#else
+#define CC_AT_DATA __data
+#endif
+
 /* Generic types. */
 typedef unsigned short uip_stats_t;
 
diff --git a/cpu/cc2430/dev/cc2430_rf.c b/cpu/cc2430/dev/cc2430_rf.c
index 5339c84cc..7d6d5ecbd 100644
--- a/cpu/cc2430/dev/cc2430_rf.c
+++ b/cpu/cc2430/dev/cc2430_rf.c
@@ -105,7 +105,7 @@ uint8_t rf_error = 0;
 PROCESS(cc2430_rf_process, "CC2430 RF driver");
 #endif
 /*---------------------------------------------------------------------------*/
-static uint8_t __data rf_flags;
+static uint8_t CC_AT_DATA rf_flags;
 static uint8_t rf_channel;
 
 static int on(void); /* prepare() needs our prototype */
diff --git a/cpu/cc2430/dev/cc2430_rf_intr.c b/cpu/cc2430/dev/cc2430_rf_intr.c
index 510c93f1a..b19a1156b 100644
--- a/cpu/cc2430/dev/cc2430_rf_intr.c
+++ b/cpu/cc2430/dev/cc2430_rf_intr.c
@@ -56,6 +56,10 @@ PROCESS_NAME(cc2430_rf_process);
  * RF interrupt service routine.
  *
  */
+#pragma save
+#if CC_CONF_OPTIMIZE_STACK_SIZE
+#pragma exclude bits
+#endif
 void
 cc2430_rf_ISR( void ) __interrupt (RF_VECTOR)
 {
@@ -75,6 +79,7 @@ cc2430_rf_ISR( void ) __interrupt (RF_VECTOR)
   ENERGEST_OFF(ENERGEST_TYPE_IRQ);
   EA = 1;
 }
+#pragma restore
 #endif
 /*---------------------------------------------------------------------------*/
 #if CC2430_RFERR_INTERRUPT
@@ -82,6 +87,10 @@ cc2430_rf_ISR( void ) __interrupt (RF_VECTOR)
  * RF error interrupt service routine.
  * Turned off by default, can be turned on in contiki-conf.h
  */
+#pragma save
+#if CC_CONF_OPTIMIZE_STACK_SIZE
+#pragma exclude bits
+#endif
 void
 cc2430_rf_error_ISR( void ) __interrupt (RFERR_VECTOR)
 {
@@ -98,5 +107,6 @@ cc2430_rf_error_ISR( void ) __interrupt (RFERR_VECTOR)
   RF_TX_LED_OFF();
   EA = 1;
 }
+#pragma restore
 #endif
 /*---------------------------------------------------------------------------*/
diff --git a/cpu/cc2430/dev/clock.c b/cpu/cc2430/dev/clock.c
index 8ca969056..e36a11297 100644
--- a/cpu/cc2430/dev/clock.c
+++ b/cpu/cc2430/dev/clock.c
@@ -51,8 +51,8 @@ volatile uint8_t sleep_flag;
 /*---------------------------------------------------------------------------*/
 /* Used in sleep timer interrupt for calculating the next interrupt time */
 static unsigned long timer_value;
-static volatile __data clock_time_t count = 0; /* Uptime in ticks */
-static volatile __data clock_time_t seconds = 0; /* Uptime in secs */
+static volatile CC_AT_DATA clock_time_t count = 0; /* Uptime in ticks */
+static volatile CC_AT_DATA clock_time_t seconds = 0; /* Uptime in secs */
 /*---------------------------------------------------------------------------*/
 /**
  * Each iteration is ~1.0xy usec, so this function delays for roughly len usec
@@ -109,6 +109,10 @@ clock_init(void)
   IEN0_STIE = 1; /* IEN0.STIE acknowledge Sleep Timer Interrupt */
 }
 /*---------------------------------------------------------------------------*/
+#pragma save
+#if CC_CONF_OPTIMIZE_STACK_SIZE
+#pragma exclude bits
+#endif
 void
 clock_ISR(void) __interrupt(ST_VECTOR)
 {
@@ -161,4 +165,5 @@ clock_ISR(void) __interrupt(ST_VECTOR)
   ENERGEST_OFF(ENERGEST_TYPE_IRQ);
   ENABLE_INTERRUPTS();
 }
+#pragma restore
 /*---------------------------------------------------------------------------*/
diff --git a/cpu/cc2430/dev/dma_intr.c b/cpu/cc2430/dev/dma_intr.c
index a2f14369d..1e8dbe2aa 100644
--- a/cpu/cc2430/dev/dma_intr.c
+++ b/cpu/cc2430/dev/dma_intr.c
@@ -32,6 +32,10 @@ extern void spi_rx_dma_callback(void);
  *
  * if callback defined a poll is made to that process
  */
+#pragma save
+#if CC_CONF_OPTIMIZE_STACK_SIZE
+#pragma exclude bits
+#endif
 void
 dma_ISR(void) __interrupt (DMA_VECTOR)
 {
@@ -65,4 +69,5 @@ dma_ISR(void) __interrupt (DMA_VECTOR)
 #endif
   EA = 1;
 }
+#pragma restore
 /*---------------------------------------------------------------------------*/
diff --git a/cpu/cc2430/dev/uart_intr.c b/cpu/cc2430/dev/uart_intr.c
index 27803f2a6..8e087791f 100644
--- a/cpu/cc2430/dev/uart_intr.c
+++ b/cpu/cc2430/dev/uart_intr.c
@@ -36,6 +36,10 @@ uart0_set_input(int (*input)(unsigned char c))
 }
 
 /*---------------------------------------------------------------------------*/
+#pragma save
+#if CC_CONF_OPTIMIZE_STACK_SIZE
+#pragma exclude bits
+#endif
 void
 uart0_rx_ISR(void) __interrupt (URX0_VECTOR)
 {
@@ -51,6 +55,7 @@ void
 uart0_tx_ISR( void ) __interrupt (UTX0_VECTOR)
 {
 }
+#pragma restore
 #endif /* UART_ZERO_ENABLE */
 #if UART_ONE_ENABLE
 /*---------------------------------------------------------------------------*/
@@ -61,6 +66,10 @@ uart1_set_input(int (*input)(unsigned char c))
 }
 /*---------------------------------------------------------------------------*/
 #if UART_ONE_CONF_WITH_INPUT
+#pragma save
+#if CC_CONF_OPTIMIZE_STACK_SIZE
+#pragma exclude bits
+#endif
 void
 uart1_rx_ISR(void) __interrupt (URX1_VECTOR)
 {
@@ -76,6 +85,7 @@ void
 uart1_tx_ISR( void ) __interrupt (UTX1_VECTOR)
 {
 }
+#pragma restore
 /*---------------------------------------------------------------------------*/
 #endif /* UART_ONE_CONF_WITH_INPUT */
 #endif /* UART_ONE_ENABLE */
diff --git a/cpu/cc2430/dev/watchdog-cc2430.c b/cpu/cc2430/dev/watchdog-cc2430.c
index 2d59d2923..47df7a1c8 100644
--- a/cpu/cc2430/dev/watchdog-cc2430.c
+++ b/cpu/cc2430/dev/watchdog-cc2430.c
@@ -47,6 +47,10 @@
 /*---------------------------------------------------------------------------*/
 /* The watchdog only throws interrupts in timer mode */
 #if WDT_TIMER_MODE
+#pragma save
+#if CC_CONF_OPTIMIZE_STACK_SIZE
+#pragma exclude bits
+#endif
 void
 cc4230_watchdog_ISR(void) __interrupt (WDT_VECTOR)
 {
@@ -57,6 +61,7 @@ cc4230_watchdog_ISR(void) __interrupt (WDT_VECTOR)
   ENERGEST_OFF(ENERGEST_TYPE_IRQ);
   EA = 1;
 }
+#pragma restore
 #endif
 /*---------------------------------------------------------------------------*/
 void
diff --git a/cpu/cc2430/rtimer-arch.c b/cpu/cc2430/rtimer-arch.c
index 517886037..d2ec784c9 100644
--- a/cpu/cc2430/rtimer-arch.c
+++ b/cpu/cc2430/rtimer-arch.c
@@ -104,6 +104,10 @@ rtimer_arch_schedule(rtimer_clock_t t)
   T1CCTL1 |= T1IM;
 }
 /*---------------------------------------------------------------------------*/
+#pragma save
+#if CC_CONF_OPTIMIZE_STACK_SIZE
+#pragma exclude bits
+#endif
 void
 cc2430_timer_1_ISR(void) __interrupt (T1_VECTOR)
 {
@@ -120,3 +124,4 @@ cc2430_timer_1_ISR(void) __interrupt (T1_VECTOR)
   ENERGEST_OFF(ENERGEST_TYPE_IRQ);
   IEN1_T1IE = 1; /* Acknowledge Timer 1 Interrupts */
 }
+#pragma restore
diff --git a/platform/sensinode/contiki-sensinode-main.c b/platform/sensinode/contiki-sensinode-main.c
index 387264e01..6899de9e8 100644
--- a/platform/sensinode/contiki-sensinode-main.c
+++ b/platform/sensinode/contiki-sensinode-main.c
@@ -33,7 +33,7 @@ PROCESS_NAME(batmon_process);
 #endif
 
 #if NETSTACK_CONF_SHORTCUTS
-static __data uint16_t len;
+static CC_AT_DATA uint16_t len;
 #endif
 
 #ifdef STARTUP_CONF_VERBOSE
diff --git a/platform/sensinode/dev/button-sensor.c b/platform/sensinode/dev/button-sensor.c
index ac239fe09..a2bda01c2 100644
--- a/platform/sensinode/dev/button-sensor.c
+++ b/platform/sensinode/dev/button-sensor.c
@@ -42,7 +42,7 @@
 #if BUTTON_SENSOR_ON
 static uint8_t p0ien;
 static uint8_t p2ien;
-static __data struct timer debouncetimer[2];
+static CC_AT_DATA struct timer debouncetimer[2];
 
 #ifdef MODEL_N740
 HWCONF_PIN(BUTTON_1, 1, 0)
@@ -143,6 +143,10 @@ int configure_b2(int type, int value)
   return 0;
 }
 /*---------------------------------------------------------------------------*/
+#pragma save
+#if CC_CONF_OPTIMIZE_STACK_SIZE
+#pragma exclude bits
+#endif
 void
 port_0_ISR(void) __interrupt (P0INT_VECTOR)
 {
@@ -194,6 +198,7 @@ port_1_ISR(void) __interrupt (P1INT_VECTOR)
   EA = 1;
 }
 #endif /* MODEL_N740 */
+#pragma restore
 
 SENSORS_SENSOR(button_1_sensor, BUTTON_1_SENSOR, value_b1, configure_b1, status_b1);
 SENSORS_SENSOR(button_2_sensor, BUTTON_2_SENSOR, value_b2, configure_b2, status_b2);
diff --git a/platform/sensinode/dev/n740.c b/platform/sensinode/dev/n740.c
index d47aa3f6a..de1e20fd1 100644
--- a/platform/sensinode/dev/n740.c
+++ b/platform/sensinode/dev/n740.c
@@ -65,12 +65,13 @@
 
 #include "dev/n740.h"
 #include "dev/uart1.h"
+#include "8051def.h"
 
 /*
  * This variable stores the most recent instruction sent to the ser-par chip.
  * We declare it as static and return its value through n740_ser_par_get().
  */
-static __data uint8_t ser_par_status;
+static CC_AT_DATA uint8_t ser_par_status;
 
 /*---------------------------------------------------------------------------*/
 /* Init the serial-parallel chip: