cpu/nrf51822: some fixes and clean up

- enabled power for uart and timer
- outsourced timer config values to periph_conf.h
- made linkerscript better readable
- adjusted default stack-sizes
- let RED_LED blink on hard_fault

cpu/nrf51822/include/cpu-conf.h

@@ -29,10 +29,10 @@
  * TODO: measure and adjust for the cortex-m0
  * @{
  */
-#define KERNEL_CONF_STACKSIZE_PRINTF    (1024)
+#define KERNEL_CONF_STACKSIZE_PRINTF    (524)
 
 #ifndef KERNEL_CONF_STACKSIZE_DEFAULT
-#define KERNEL_CONF_STACKSIZE_DEFAULT   (1024)
+#define KERNEL_CONF_STACKSIZE_DEFAULT   (524)
 #endif
 
 #define KERNEL_CONF_STACKSIZE_IDLE      (256)

cpu/nrf51822/nrf51822qfaa_linkerscript.ld

@@ -34,8 +34,8 @@ SEARCH_DIR(.)
 /* Memory Spaces Definitions */
 MEMORY
 {
-    rom (rx)    : ORIGIN = 0x00000000, LENGTH = 0x40000		/* 256K flash */
-    ram (rwx)   : ORIGIN = 0x20000000, LENGTH = 0x4000		/* 16K ram */
+    rom (rx)    : ORIGIN = 0x00000000, LENGTH = 256K
+    ram (rwx)   : ORIGIN = 0x20000000, LENGTH = 16K
 }
 
 /* The stack size used by the application. NOTE: you need to adjust  */

cpu/nrf51822/periph/timer.c

@@ -43,30 +43,32 @@ static timer_conf_t timer_config[TIMER_NUMOF];
 
 int timer_init(tim_t dev, unsigned int ticks_per_us, void (*callback)(int))
 {
-
     NRF_TIMER_Type *timer;
 
     switch (dev) {
 #if TIMER_0_EN
         case TIMER_0:
             timer = TIMER_0_DEV;
-            timer->BITMODE = TIMER_BITMODE_BITMODE_32Bit;    /* 32 Bit Mode */
+            timer->POWER = 1;
+            timer->BITMODE = TIMER_0_BITMODE;
             NVIC_SetPriority(TIMER_0_IRQ, TIMER_IRQ_PRIO);
             NVIC_EnableIRQ(TIMER_0_IRQ);
             break;
 #endif
 #if TIMER_1_EN
         case TIMER_1:
             timer = TIMER_1_DEV;
-            timer->BITMODE = TIMER_BITMODE_BITMODE_16Bit;    /* 16 Bit Mode */
+            timer->POWER = 1;
+            timer->BITMODE = TIEMR_1_BITMODE;
             NVIC_SetPriority(TIMER_1_IRQ, TIMER_IRQ_PRIO);
             NVIC_EnableIRQ(TIMER_1_IRQ);
             break;
 #endif
 #if TIMER_2_EN
         case TIMER_2:
             timer = TIMER_2_DEV;
-            timer->BITMODE = TIMER_BITMODE_BITMODE_16Bit;    /* 16 Bit Mode */
+            timer->POWER = 1;
+            timer->BITMODE = TIMER_2_BITMODE;
             NVIC_SetPriority(TIMER_2_IRQ, TIMER_IRQ_PRIO);
             NVIC_EnableIRQ(TIMER_2_IRQ);
             break;
@@ -102,14 +104,17 @@ int timer_init(tim_t dev, unsigned int ticks_per_us, void (*callback)(int))
         default:
             return -1;
     }
-    /* timer->INTENSET = TIMER_INTENSET_COMPARE0_Enabled << TIMER_INTENSET_COMPARE0_Pos; */
+
+    /* clear all compare channels */
     timer->SHORTS = (TIMER_SHORTS_COMPARE0_CLEAR_Enabled << TIMER_SHORTS_COMPARE0_CLEAR_Pos);
     timer->SHORTS = (TIMER_SHORTS_COMPARE1_CLEAR_Enabled << TIMER_SHORTS_COMPARE1_CLEAR_Pos);
     timer->SHORTS = (TIMER_SHORTS_COMPARE2_CLEAR_Enabled << TIMER_SHORTS_COMPARE2_CLEAR_Pos);
     timer->SHORTS = (TIMER_SHORTS_COMPARE3_CLEAR_Enabled << TIMER_SHORTS_COMPARE3_CLEAR_Pos);
+
+    /* start the timer */
     timer->TASKS_START = 1;
 
-    return 1;
+    return 0;
 }
 
 int timer_set(tim_t dev, int channel, unsigned int timeout)

cpu/nrf51822/periph/uart.c

@@ -15,6 +15,7 @@
  *
  * @author      Christian Kühling <kuehling@zedat.fu-berlin.de>
  * @author      Timo Ziegler <timo.ziegler@fu-berlin.de>
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  *
  * @}
  */
@@ -117,18 +118,29 @@ int uart_init_blocking(uart_t uart, uint32_t baudrate)
     switch (uart) {
 #if UART_0_EN
         case UART_0:
+            /* power on UART device */
+            UART_0_DEV->POWER = 1;
+
             /* reset configuration registers */
             UART_0_DEV->CONFIG = 0;
 
             /* select baudrate */
             UART_0_DEV->BAUDRATE = baudrate_real;
 
+            /* configure RX/TX pin modes */
+            NRF_GPIO->DIRSET = (1 << UART_0_PIN_TX);
+            NRF_GPIO->DIRCLR = (1 << UART_0_PIN_RX);
+
             /* configure UART pins to use */
             UART_0_DEV->PSELTXD = UART_0_PIN_TX;
             UART_0_DEV->PSELRXD = UART_0_PIN_RX;
 
             /* enable hw-flow control if defined */
 #if UART_0_HWFLOWCTRL
+            /* set pin mode for RTS and CTS pins */
+            NRF_GPIO->DIRSET = (1 << UART_0_PIN_RTS);
+            NRF_GPIO->DIRSET = (1 << UART_0_PIN_CTS);
+            /* configure RTS and CTS pins to use */
             UART_0_DEV->PSELRTS = UART_0_PIN_RTS;
             UART_0_DEV->PSELCTS = UART_0_PIN_CTS;
             UART_0_DEV->CONFIG |= 1;        /* enable HW flow control */
@@ -147,8 +159,6 @@ int uart_init_blocking(uart_t uart, uint32_t baudrate)
 #endif
     }
 
-    DEBUG("UART INITIALIZATION complete\n");
-
     return 0;
 }
 
@@ -208,4 +218,30 @@ int uart_write_blocking(uart_t uart, char data)
     return 1;
 }
 
+void uart_poweron(uart_t uart)
+{
+    switch (uart) {
+#if UART_0_EN
+        case UART_0:
+            UART_0_DEV->POWER = 1;
+            break;
+#endif
+        default:
+            return;
+    }
+}
+
+void uart_poweroff(uart_t uart)
+{
+    switch (uart) {
+#if UART_0_EN
+        case UART_0:
+            UART_0_DEV->POWER = 0;
+            break;
+#endif
+        default:
+            return;
+    }
+}
+
 #endif /* UART_NUMOF */

cpu/nrf51822/startup.c

@@ -90,8 +90,12 @@ void isr_nmi(void)
 
 void isr_hard_fault(void)
 {
-    LED_RED_ON;
-    while (1) {asm ("nop");}
+    while (1) {
+        for (int i = 0; i < 500000; i++) {
+            asm("nop");
+        }
+        LED_RED_TOGGLE;
+    }
 }
 
 /* Cortex-M specific interrupt vectors */