diff --git a/core/dev/spi.h b/core/dev/spi.h
index 1ccbe2bc0..5960c411b 100644
--- a/core/dev/spi.h
+++ b/core/dev/spi.h
@@ -57,36 +57,36 @@ extern unsigned char spi_busy;
 void spi_init(void);
 
 /* Write one character to SPI */
-#define SPI_WRITE(data)                         \
-  do {                                          \
-    SPI_WAITFORTx_BEFORE();                     \
-    SPI_TXBUF = data;                           \
-    SPI_WAITFOREOTx();                          \
+#define SPI_WRITE(data) \
+  do { \
+    SPI_WAITFORTx_BEFORE(); \
+    SPI_TXBUF = data; \
+    SPI_WAITFOREOTx(); \
   } while(0)
 
 /* Write one character to SPI - will not wait for end
    useful for multiple writes with wait after final */
-#define SPI_WRITE_FAST(data)                    \
-  do {                                          \
-    SPI_WAITFORTx_BEFORE();                     \
-    SPI_TXBUF = data;                           \
-    SPI_WAITFORTx_AFTER();                      \
+#define SPI_WRITE_FAST(data) \
+  do { \
+    SPI_WAITFORTx_BEFORE(); \
+    SPI_TXBUF = data; \
+    SPI_WAITFORTx_AFTER(); \
   } while(0)
 
 /* Read one character from SPI */
-#define SPI_READ(data)   \
-  do {                   \
-    SPI_TXBUF = 0;       \
-    SPI_WAITFOREORx();   \
-    data = SPI_RXBUF;    \
+#define SPI_READ(data) \
+  do { \
+    SPI_TXBUF = 0; \
+    SPI_WAITFOREORx(); \
+    data = SPI_RXBUF; \
   } while(0)
 
 /* Flush the SPI read register */
 #ifndef SPI_FLUSH
 #define SPI_FLUSH() \
-  do {              \
-    SPI_RXBUF;      \
-  } while(0);
+  do { \
+    SPI_RXBUF; \
+  } while(0)
 #endif
 
 #endif /* SPI_H_ */
diff --git a/core/sys/cc.h b/core/sys/cc.h
index 90ef3e710..6bd87c288 100644
--- a/core/sys/cc.h
+++ b/core/sys/cc.h
@@ -129,12 +129,18 @@
 
 #define CC_CONCAT2(s1, s2) s1##s2
 /**
- * A C preprocessing macro for concatenating to
- * strings.
+ * A C preprocessing macro for concatenating two preprocessor tokens.
  *
  * We need use two macros (CC_CONCAT and CC_CONCAT2) in order to allow
  * concatenation of two \#defined macros.
  */
 #define CC_CONCAT(s1, s2) CC_CONCAT2(s1, s2)
+#define CC_CONCAT_EXT_2(s1, s2) CC_CONCAT2(s1, s2)
+
+/**
+ * A C preprocessing macro for concatenating three preprocessor tokens.
+ */
+#define CC_CONCAT3(s1, s2, s3) s1##s2##s3
+#define CC_CONCAT_EXT_3(s1, s2, s3) CC_CONCAT3(s1, s2, s3)
 
 #endif /* CC_H_ */
diff --git a/cpu/cc2538/dev/spi.c b/cpu/cc2538/dev/spi.c
index bff1783b5..6b363bd7b 100644
--- a/cpu/cc2538/dev/spi.c
+++ b/cpu/cc2538/dev/spi.c
@@ -1,5 +1,9 @@
 /*
  * Copyright (c) 2013, University of Michigan.
+ *
+ * Copyright (c) 2015, Weptech elektronik GmbH
+ * Author: Ulf Knoblich, ulf.knoblich@weptech.de
+ *
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -41,102 +45,281 @@
 #include "dev/spi.h"
 #include "dev/ssi.h"
 #include "dev/gpio.h"
+/*---------------------------------------------------------------------------*/
+/* Check port / pin settings for SPI0 and provide default values for spi_cfg */
+#ifndef SPI0_CLK_PORT
+#define SPI0_CLK_PORT         (-1)
+#endif
+#ifndef SPI0_CLK_PIN
+#define SPI0_CLK_PIN          (-1)
+#endif
+#if SPI0_CLK_PORT >= 0 && SPI0_CLK_PIN < 0 || \
+  SPI0_CLK_PORT < 0 && SPI0_CLK_PIN >= 0
+#error Both SPI0_CLK_PORT and SPI0_CLK_PIN must be valid or invalid
+#endif
 
-#define SPI_CLK_PORT_BASE        GPIO_PORT_TO_BASE(SPI_CLK_PORT)
-#define SPI_CLK_PIN_MASK         GPIO_PIN_MASK(SPI_CLK_PIN)
-#define SPI_MOSI_PORT_BASE       GPIO_PORT_TO_BASE(SPI_MOSI_PORT)
-#define SPI_MOSI_PIN_MASK        GPIO_PIN_MASK(SPI_MOSI_PIN)
-#define SPI_MISO_PORT_BASE       GPIO_PORT_TO_BASE(SPI_MISO_PORT)
-#define SPI_MISO_PIN_MASK        GPIO_PIN_MASK(SPI_MISO_PIN)
+#ifndef SPI0_TX_PORT
+#define SPI0_TX_PORT          (-1)
+#endif
+#ifndef SPI0_TX_PIN
+#define SPI0_TX_PIN           (-1)
+#endif
+#if SPI0_TX_PORT >= 0 && SPI0_TX_PIN < 0 || \
+  SPI0_TX_PORT < 0 && SPI0_TX_PIN >= 0
+#error Both SPI0_TX_PORT and SPI0_TX_PIN must be valid or invalid
+#endif
 
-/**
- * \brief Initialize the SPI bus.
- *
- * This SPI init() function uses the following defines to set the pins:
- *    SPI_CLK_PORT               SPI_CLK_PIN
- *    SPI_MOSI_PORT              SPI_MOSI_PIN
- *    SPI_MISO_PORT              SPI_MISO_PIN
- *
- * This sets the mode to Motorola SPI with the following format options:
- *    Clock phase:               1; data captured on second (rising) edge
- *    Clock polarity:            1; clock is high when idle
- *    Data size:                 8 bits
- */
+#ifndef SPI0_RX_PORT
+#define SPI0_RX_PORT          (-1)
+#endif
+#ifndef SPI0_RX_PIN
+#define SPI0_RX_PIN           (-1)
+#endif
+#if SPI0_RX_PORT >= 0 && SPI0_RX_PIN < 0 || \
+  SPI0_RX_PORT < 0 && SPI0_RX_PIN >= 0
+#error Both SPI0_RX_PORT and SPI0_RX_PIN must be valid or invalid
+#endif
+
+/* Here we check that either all or none of the ports are defined. As
+   we did already check that both ports + pins are either defined or
+   not for every pin, this means that we can check for an incomplete
+   configuration by only looking at the port defines */
+/* If some SPI0 pads are valid */
+#if SPI0_CLK_PORT >= 0 || SPI0_TX_PORT >= 0 || SPI0_RX_PORT >= 0
+/* but not all */
+#if SPI0_CLK_PORT < 0 || SPI0_TX_PORT < 0 || SPI0_RX_PORT < 0
+#error Some SPI0 pad definitions are invalid
+#endif
+#define SPI0_PADS_VALID
+#endif
+/*---------------------------------------------------------------------------*/
+/* Check port / pin settings for SPI1 and provide default values for spi_cfg */
+#ifndef SPI1_CLK_PORT
+#define SPI1_CLK_PORT         (-1)
+#endif
+#ifndef SPI1_CLK_PIN
+#define SPI1_CLK_PIN          (-1)
+#endif
+#if SPI1_CLK_PORT >= 0 && SPI1_CLK_PIN < 0 || \
+  SPI1_CLK_PORT < 0 && SPI1_CLK_PIN >= 0
+#error Both SPI1_CLK_PORT and SPI1_CLK_PIN must be valid or invalid
+#endif
+
+#ifndef SPI1_TX_PORT
+#define SPI1_TX_PORT          (-1)
+#endif
+#ifndef SPI1_TX_PIN
+#define SPI1_TX_PIN           (-1)
+#endif
+#if SPI1_TX_PORT >= 0 && SPI1_TX_PIN < 0 || \
+  SPI1_TX_PORT < 0 && SPI1_TX_PIN >= 0
+#error Both SPI1_TX_PORT and SPI1_TX_PIN must be valid or invalid
+#endif
+
+#ifndef SPI1_RX_PORT
+#define SPI1_RX_PORT          (-1)
+#endif
+#ifndef SPI1_RX_PIN
+#define SPI1_RX_PIN           (-1)
+#endif
+#if SPI1_RX_PORT >= 0 && SPI1_RX_PIN < 0 || \
+  SPI1_RX_PORT < 0 && SPI1_RX_PIN >= 0
+#error Both SPI1_RX_PORT and SPI1_RX_PIN must be valid or invalid
+#endif
+
+/* If some SPI1 pads are valid */
+#if SPI1_CLK_PORT >= 0 || SPI1_TX_PORT >= 0 || SPI1_RX_PORT >= 0
+/* but not all */
+#if SPI1_CLK_PORT < 0 || SPI1_TX_PORT < 0 || SPI1_RX_PORT < 0
+#error Some SPI1 pad definitions are invalid
+#endif
+#define SPI1_PADS_VALID
+#endif
+
+#ifdef SPI_DEFAULT_INSTANCE
+#if SPI_DEFAULT_INSTANCE == 0
+#ifndef SPI0_PADS_VALID
+#error SPI_DEFAULT_INSTANCE is set to SPI0, but its pads are not valid
+#endif
+#elif SPI_DEFAULT_INSTANCE == 1
+#ifndef SPI1_PADS_VALID
+#error SPI_DEFAULT_INSTANCE is set to SPI1, but its pads are not valid
+#endif
+#endif
+#endif
+
+#if (SPI0_CPRS_CPSDVSR & 1) == 1 || SPI0_CPRS_CPSDVSR < 2 || SPI0_CPRS_CPSDVSR > 254
+#error SPI0_CPRS_CPSDVSR must be an even number between 2 and 254
+#endif
+
+#if (SPI1_CPRS_CPSDVSR & 1) == 1 || SPI1_CPRS_CPSDVSR < 2 || SPI1_CPRS_CPSDVSR > 254
+#error SPI1_CPRS_CPSDVSR must be an even number between 2 and 254
+#endif
+
+/*---------------------------------------------------------------------------*/
+typedef struct {
+  int8_t port;
+  int8_t pin;
+} spi_pad_t;
+typedef struct {
+  uint32_t base;
+  uint32_t ioc_ssirxd_ssi;
+  uint32_t ioc_pxx_sel_ssi_clkout;
+  uint32_t ioc_pxx_sel_ssi_txd;
+  uint8_t ssi_cprs_cpsdvsr;
+  spi_pad_t clk;
+  spi_pad_t tx;
+  spi_pad_t rx;
+} spi_regs_t;
+/*---------------------------------------------------------------------------*/
+static const spi_regs_t spi_regs[SSI_INSTANCE_COUNT] = {
+  {
+    .base = SSI0_BASE,
+    .ioc_ssirxd_ssi = IOC_SSIRXD_SSI0,
+    .ioc_pxx_sel_ssi_clkout = IOC_PXX_SEL_SSI0_CLKOUT,
+    .ioc_pxx_sel_ssi_txd = IOC_PXX_SEL_SSI0_TXD,
+    .ssi_cprs_cpsdvsr = SPI0_CPRS_CPSDVSR,
+    .clk = { SPI0_CLK_PORT, SPI0_CLK_PIN },
+    .tx = { SPI0_TX_PORT, SPI0_TX_PIN },
+    .rx = { SPI0_RX_PORT, SPI0_RX_PIN }
+  }, {
+    .base = SSI1_BASE,
+    .ioc_ssirxd_ssi = IOC_SSIRXD_SSI1,
+    .ioc_pxx_sel_ssi_clkout = IOC_PXX_SEL_SSI1_CLKOUT,
+    .ioc_pxx_sel_ssi_txd = IOC_PXX_SEL_SSI1_TXD,
+    .ssi_cprs_cpsdvsr = SPI1_CPRS_CPSDVSR,
+    .clk = { SPI1_CLK_PORT, SPI1_CLK_PIN },
+    .tx = { SPI1_TX_PORT, SPI1_TX_PIN },
+    .rx = { SPI1_RX_PORT, SPI1_RX_PIN }
+  }
+};
+/*---------------------------------------------------------------------------*/
+/* Deprecated function call provided for compatibility reasons */
+#ifdef SPI_DEFAULT_INSTANCE
 void
 spi_init(void)
 {
-  spi_enable();
+  spix_init(SPI_DEFAULT_INSTANCE);
+}
+#endif /* #ifdef SPI_DEFAULT_INSTANCE */
+/*---------------------------------------------------------------------------*/
+void
+spix_init(uint8_t spi)
+{
+  const spi_regs_t *regs;
+
+  if(spi >= SSI_INSTANCE_COUNT) {
+    return;
+  }
+
+  regs = &spi_regs[spi];
+
+  if(regs->clk.port < 0) {
+    /* Port / pin configuration invalid. We checked for completeness
+       above. If clk.port is < 0, this means that all other defines are
+       < 0 as well */
+    return;
+  }
+
+  spix_enable(spi);
 
   /* Start by disabling the peripheral before configuring it */
-  REG(SSI0_BASE + SSI_CR1) = 0;
+  REG(regs->base + SSI_CR1) = 0;
 
   /* Set the IO clock as the SSI clock */
-  REG(SSI0_BASE + SSI_CC) = 1;
+  REG(regs->base + SSI_CC) = 1;
 
   /* Set the mux correctly to connect the SSI pins to the correct GPIO pins */
-  ioc_set_sel(SPI_CLK_PORT, SPI_CLK_PIN, IOC_PXX_SEL_SSI0_CLKOUT);
-  ioc_set_sel(SPI_MOSI_PORT, SPI_MOSI_PIN, IOC_PXX_SEL_SSI0_TXD);
-  REG(IOC_SSIRXD_SSI0) = (SPI_MISO_PORT * 8) + SPI_MISO_PIN;
+  ioc_set_sel(regs->clk.port,
+              regs->clk.pin,
+              regs->ioc_pxx_sel_ssi_clkout);
+  ioc_set_sel(regs->tx.port,
+              regs->tx.pin,
+              regs->ioc_pxx_sel_ssi_txd);
+  REG(regs->ioc_ssirxd_ssi) = (regs->rx.port * 8) + regs->rx.pin;
 
   /* Put all the SSI gpios into peripheral mode */
-  GPIO_PERIPHERAL_CONTROL(SPI_CLK_PORT_BASE, SPI_CLK_PIN_MASK);
-  GPIO_PERIPHERAL_CONTROL(SPI_MOSI_PORT_BASE, SPI_MOSI_PIN_MASK);
-  GPIO_PERIPHERAL_CONTROL(SPI_MISO_PORT_BASE, SPI_MISO_PIN_MASK);
+  GPIO_PERIPHERAL_CONTROL(GPIO_PORT_TO_BASE(regs->clk.port),
+                          GPIO_PIN_MASK(regs->clk.pin));
+  GPIO_PERIPHERAL_CONTROL(GPIO_PORT_TO_BASE(regs->tx.port),
+                          GPIO_PIN_MASK(regs->tx.pin));
+  GPIO_PERIPHERAL_CONTROL(GPIO_PORT_TO_BASE(regs->rx.port),
+                          GPIO_PIN_MASK(regs->rx.pin));
 
   /* Disable any pull ups or the like */
-  ioc_set_over(SPI_CLK_PORT, SPI_CLK_PIN, IOC_OVERRIDE_DIS);
-  ioc_set_over(SPI_MOSI_PORT, SPI_MOSI_PIN, IOC_OVERRIDE_DIS);
-  ioc_set_over(SPI_MISO_PORT, SPI_MISO_PIN, IOC_OVERRIDE_DIS);
+  ioc_set_over(regs->clk.port, regs->clk.pin, IOC_OVERRIDE_DIS);
+  ioc_set_over(regs->tx.port, regs->tx.pin, IOC_OVERRIDE_DIS);
+  ioc_set_over(regs->rx.port, regs->rx.pin, IOC_OVERRIDE_DIS);
 
   /* Configure the clock */
-  REG(SSI0_BASE + SSI_CPSR) = 2;
+  REG(regs->base + SSI_CPSR) = regs->ssi_cprs_cpsdvsr;
 
-  /* Configure the default SPI options.
+  /*
+   * Configure the default SPI options.
    *   mode:  Motorola frame format
    *   clock: High when idle
    *   data:  Valid on rising edges of the clock
    *   bits:  8 byte data
    */
-  REG(SSI0_BASE + SSI_CR0) = SSI_CR0_SPH | SSI_CR0_SPO | (0x07);
+  REG(regs->base + SSI_CR0) = SSI_CR0_SPH | SSI_CR0_SPO | (0x07);
 
   /* Enable the SSI */
-  REG(SSI0_BASE + SSI_CR1) |= SSI_CR1_SSE;
+  REG(regs->base + SSI_CR1) |= SSI_CR1_SSE;
 }
 /*---------------------------------------------------------------------------*/
 void
-spi_cs_init(uint8_t port, uint8_t pin)
+spix_enable(uint8_t spi)
 {
-  GPIO_SOFTWARE_CONTROL(GPIO_PORT_TO_BASE(port), GPIO_PIN_MASK(pin));
+  if(spi >= SSI_INSTANCE_COUNT) {
+    return;
+  }
+  REG(SYS_CTRL_RCGCSSI) |= (1 << spi);
+}
+/*---------------------------------------------------------------------------*/
+void
+spix_disable(uint8_t spi)
+{
+  if(spi >= SSI_INSTANCE_COUNT) {
+    return;
+  }
+  REG(SYS_CTRL_RCGCSSI) &= ~(1 << spi);
+}
+/*---------------------------------------------------------------------------*/
+void
+spix_set_mode(uint8_t spi,
+              uint32_t frame_format,
+              uint32_t clock_polarity,
+              uint32_t clock_phase,
+              uint32_t data_size)
+{
+  const spi_regs_t *regs;
+
+  if(spi >= SSI_INSTANCE_COUNT) {
+    return;
+  }
+
+  regs = &spi_regs[spi];
+
+  /* Disable the SSI peripheral to configure it */
+  REG(regs->base + SSI_CR1) = 0;
+
+  /* Configure the SSI options */
+  REG(regs->base + SSI_CR0) = clock_phase |
+    clock_polarity |
+    frame_format |
+    (data_size - 1);
+
+  /* Re-enable the SSI */
+  REG(regs->base + SSI_CR1) |= SSI_CR1_SSE;
+}
+/*---------------------------------------------------------------------------*/
+void
+spix_cs_init(uint8_t port, uint8_t pin)
+{
+  GPIO_SOFTWARE_CONTROL(GPIO_PORT_TO_BASE(port),
+                        GPIO_PIN_MASK(pin));
   ioc_set_over(port, pin, IOC_OVERRIDE_DIS);
   GPIO_SET_OUTPUT(GPIO_PORT_TO_BASE(port), GPIO_PIN_MASK(pin));
   GPIO_SET_PIN(GPIO_PORT_TO_BASE(port), GPIO_PIN_MASK(pin));
 }
-/*---------------------------------------------------------------------------*/
-void
-spi_enable(void)
-{
-  /* Enable the clock for the SSI peripheral */
-  REG(SYS_CTRL_RCGCSSI) |= 1;
-}
-/*---------------------------------------------------------------------------*/
-void
-spi_disable(void)
-{
-  /* Gate the clock for the SSI peripheral */
-  REG(SYS_CTRL_RCGCSSI) &= ~1;
-}
-/*---------------------------------------------------------------------------*/
-void
-spi_set_mode(uint32_t frame_format, uint32_t clock_polarity,
-             uint32_t clock_phase, uint32_t data_size)
-{
-  /* Disable the SSI peripheral to configure it */
-  REG(SSI0_BASE + SSI_CR1) = 0;
-
-  /* Configure the SSI options */
-  REG(SSI0_BASE + SSI_CR0) = clock_phase | clock_polarity | frame_format | (data_size - 1);
-
-  /* Re-enable the SSI */
-  REG(SSI0_BASE + SSI_CR1) |= SSI_CR1_SSE;
-}
 /** @} */
diff --git a/cpu/cc2538/dev/ssi.h b/cpu/cc2538/dev/ssi.h
index da41a5b0a..ca06969ee 100644
--- a/cpu/cc2538/dev/ssi.h
+++ b/cpu/cc2538/dev/ssi.h
@@ -45,6 +45,12 @@
 #ifndef SSI_H_
 #define SSI_H_
 
+/*---------------------------------------------------------------------------*/
+/** \name Number of SSI instances supported by this CPU.
+ * @{
+ */
+#define SSI_INSTANCE_COUNT  2
+/** @} */
 /*---------------------------------------------------------------------------*/
 /** \name Base register memory locations.
  * @{
diff --git a/cpu/cc2538/spi-arch.h b/cpu/cc2538/spi-arch.h
index ddbf9daac..137220b2f 100644
--- a/cpu/cc2538/spi-arch.h
+++ b/cpu/cc2538/spi-arch.h
@@ -1,5 +1,9 @@
 /*
  * Copyright (c) 2013, University of Michigan.
+ *
+ * Copyright (c) 2015, Weptech elektronik GmbH
+ * Author: Ulf Knoblich, ulf.knoblich@weptech.de
+ *
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -34,65 +38,144 @@
  * Header file for the cc2538 SPI driver, including macros for the
  * implementation of the low-level SPI primitives such as waiting for the TX
  * FIFO to be ready, inserting into the TX FIFO, etc.
+ *
+ * It supports the usage of SSI_NUM_INSTANCES instances by providing new
+ * functions calls like
+ *
+ * - spix_init(uint8_t instance)
+ * - spix_enable(uint8_t instance)
+ * - spix_disable(uint8_t instance)
+ * - spix_set_mode(unit8_t instance, ...)
+ *
+ * and new macros like
+ *
+ * - SPIX_WAITFORTxREADY(x)
+ * - SPIX_WAITFOREOTx(x)
+ * - SPIX_WAITFOREORx(x)
+ * - SPIX_FLUSH(x)
+ *
+ * Some of the old functions and macros are still supported.
+ * When using these deprecated functions, the SSI module to use 
+ * has to be be selected by means of the macro SPI_CONF_DEFAULT_INSTANCE.
+ *
+ * This SPI driver depends on the following defines:
+ *
+ * For the SSI0 module:
+ *
+ * - SPI0_CKL_PORT
+ * - SPI0_CLK_PIN
+ * - SPI0_TX_PORT
+ * - SPI0_TX_PIN
+ * - SPI0_RX_PORT
+ * - SPI0_RX_PIN
+ *
+ * For the SSI1 module:
+ *
+ * - SPI1_CKL_PORT
+ * - SPI1_CLK_PIN
+ * - SPI1_TX_PORT
+ * - SPI1_TX_PIN
+ * - SPI1_RX_PORT
+ * - SPI1_RX_PIN
  */
 #ifndef SPI_ARCH_H_
 #define SPI_ARCH_H_
 
+#include "contiki.h"
+
 #include "dev/ssi.h"
-
-#define SPI_WAITFORTxREADY() do { \
-  while(!(REG(SSI0_BASE + SSI_SR) & SSI_SR_TNF)); \
-} while(0)
-
-#define SPI_TXBUF REG(SSI0_BASE + SSI_DR)
-
-#define SPI_RXBUF REG(SSI0_BASE + SSI_DR)
-
-#define SPI_WAITFOREOTx() do { \
-  while(REG(SSI0_BASE + SSI_SR) & SSI_SR_BSY); \
-} while(0)
-
-#define SPI_WAITFOREORx() do { \
-  while(!(REG(SSI0_BASE + SSI_SR) & SSI_SR_RNE)); \
-} while(0)
-
-#ifdef SPI_FLUSH
-#error "You must include spi-arch.h before spi.h for the CC2538."
+/*---------------------------------------------------------------------------*/
+/* The SPI instance to use when using the deprecated SPI API. */
+#ifdef SPI_CONF_DEFAULT_INSTANCE
+#if SPI_CONF_DEFAULT_INSTANCE > (SSI_INSTANCE_COUNT - 1)
+#error Invalid SPI_CONF_DEFAULT_INSTANCE: valid values are 0 and 1
+#else
+#define SPI_DEFAULT_INSTANCE            SPI_CONF_DEFAULT_INSTANCE
+#endif
+#endif
+/*---------------------------------------------------------------------------*/
+/* Default values for the clock rate divider */
+#ifdef SPI0_CONF_CPRS_CPSDVSR 
+#define SPI0_CPRS_CPSDVSR               SPI0_CONF_CPRS_CPSDVSR 
+#else
+#define SPI0_CPRS_CPSDVSR               2
 #endif
-#define SPI_FLUSH() do { \
-  while (REG(SSI0_BASE + SSI_SR) & SSI_SR_RNE) { \
-    SPI_RXBUF; \
-  } \
-} while(0)
 
-#define SPI_CS_CLR(port, pin) do { \
-  GPIO_CLR_PIN(GPIO_PORT_TO_BASE(port), GPIO_PIN_MASK(pin)); \
+#ifdef SPI1_CONF_CPRS_CPSDVSR 
+#define SPI1_CPRS_CPSDVSR               SPI1_CONF_CPRS_CPSDVSR 
+#else
+#define SPI1_CPRS_CPSDVSR               2
+#endif
+/*---------------------------------------------------------------------------*/
+/* New API macros */
+#define SPIX_WAITFORTxREADY(spi) do { \
+    while(!(REG(CC_CONCAT3(SSI, spi, _BASE) + SSI_SR) & SSI_SR_TNF)) ; \
 } while(0)
-
-#define SPI_CS_SET(port, pin) do { \
-  GPIO_SET_PIN(GPIO_PORT_TO_BASE(port), GPIO_PIN_MASK(pin)); \
+#define SPIX_BUF(spi)                   REG(CC_CONCAT3(SSI, spi, _BASE) + SSI_DR)
+#define SPIX_WAITFOREOTx(spi) do { \
+    while(REG(CC_CONCAT3(SSI, spi, _BASE) + SSI_SR) & SSI_SR_BSY) ; \
 } while(0)
+#define SPIX_WAITFOREORx(spi) do { \
+    while(!(REG(CC_CONCAT3(SSI, spi, _BASE) + SSI_SR) & SSI_SR_RNE)) ; \
+} while(0)
+#define SPIX_FLUSH(spi) do { \
+    while(REG(CC_CONCAT3(SSI, spi, _BASE) + SSI_SR) & SSI_SR_RNE) { \
+        SPIX_BUF(spi);                                           \
+    } \
+} while(0)
+#define SPIX_CS_CLR(port, pin) do { \
+    GPIO_CLR_PIN(GPIO_PORT_TO_BASE(port), GPIO_PIN_MASK(pin)); \
+} while(0)
+#define SPIX_CS_SET(port, pin) do { \
+    GPIO_SET_PIN(GPIO_PORT_TO_BASE(port), GPIO_PIN_MASK(pin)); \
+} while(0)
+/*---------------------------------------------------------------------------*/
+/* Deprecated macros provided for compatibility reasons */
+#ifdef SPI_DEFAULT_INSTANCE
+#define SPI_WAITFORTxREADY()            SPIX_WAITFORTxREADY(SPI_DEFAULT_INSTANCE)
+#define SPI_TXBUF                       SPIX_BUF(SPI_DEFAULT_INSTANCE)
+#define SPI_RXBUF                       SPI_TXBUF
+#define SPI_WAITFOREOTx()               SPIX_WAITFOREOTx(SPI_DEFAULT_INSTANCE)
+#define SPI_WAITFOREORx()               SPIX_WAITFOREORx(SPI_DEFAULT_INSTANCE)
+#ifdef SPI_FLUSH
+#error You must include spi-arch.h before spi.h for the CC2538
+#else
+#define SPI_FLUSH()                     SPIX_FLUSH(SPI_DEFAULT_INSTANCE)
+#endif
+#define SPI_CS_CLR(port, pin)           SPIX_CS_CLR(port, pin)
+#define SPI_CS_SET(port, pin)           SPIX_CS_SET(port, pin)
+#endif  /* #ifdef SPI_DEFAULT_INSTANCE */
 /*---------------------------------------------------------------------------*/
 /** \name Arch-specific SPI functions
  * @{
  */
 
 /**
- * \brief Configure a GPIO to be the chip select pin
+ * \brief Initialize the SPI bus for the instance given
+ *
+ * This sets the mode to Motorola SPI with the following format options:
+ *    Clock phase:               1; data captured on second (rising) edge
+ *    Clock polarity:            1; clock is high when idle
+ *    Data size:                 8 bits
+ *
+ * Use spix_set_mode() to change the spi mode.
  */
-void spi_cs_init(uint8_t port, uint8_t pin);
-
-/** \brief Enables the SPI peripheral
- */
-void spi_enable(void);
-
-/** \brief Disables the SPI peripheral
- * \note Call this function to save power when the SPI is unused.
- */
-void spi_disable(void);
+void spix_init(uint8_t spi);
 
 /**
- * \brief Configure the SPI data and clock polarity and the data size.
+ * \brief Enables the SPI peripheral for the instance given
+ */
+void spix_enable(uint8_t spi);
+
+/**
+ * \brief Disables the SPI peripheral for the instance given
+ * \note Call this function to save power when the SPI is unused.
+ */
+void spix_disable(uint8_t spi);
+
+/**
+ * \brief Configure the SPI data and clock polarity and the data size for the
+ * instance given
  *
  * This function configures the SSI peripheral to use a particular SPI
  * configuration that a slave device requires. It should always be called
@@ -100,6 +183,7 @@ void spi_disable(void);
  *
  * See section 19.4.4 in the CC2538 user guide for more information.
  *
+ * \param spi            The SSI instance to use.       
  * \param frame_format   Set the SSI frame format. Use SSI_CR0_FRF_MOTOROLA,
  *                       SSI_CR0_FRF_TI, or SSI_CR0_FRF_MICROWIRE.
  * \param clock_polarity In Motorola mode, set whether the clock is high or low
@@ -109,8 +193,17 @@ void spi_disable(void);
  * \param data_size      The number of bits in each "byte" of data. Must be
  *                       between 4 and 16, inclusive.
  */
-void spi_set_mode(uint32_t frame_format, uint32_t clock_polarity,
-                  uint32_t clock_phase, uint32_t data_size);
+void spix_set_mode(uint8_t spi, uint32_t frame_format,
+                   uint32_t clock_polarity, uint32_t clock_phase,
+                   uint32_t data_size);
+
+/**
+ * \brief Configure a GPIO to be the chip select pin.
+ *
+ * Even if this function does not depend on the SPI instance used, we rename
+ * it to reflect the new naming convention.
+ */
+void spix_cs_init(uint8_t port, uint8_t pin);
 
 /** @} */
 
diff --git a/platform/cc2538dk/dev/board.h b/platform/cc2538dk/dev/board.h
index d5514839d..2d9c5ac48 100644
--- a/platform/cc2538dk/dev/board.h
+++ b/platform/cc2538dk/dev/board.h
@@ -28,7 +28,7 @@
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-/** 
+/**
  * \addtogroup cc2538dk
  * @{
  *
@@ -78,28 +78,28 @@
 #undef LEDS_RED
 #undef LEDS_CONF_ALL
 
-#define LEDS_YELLOW    2 /**< LED2 (Yellow) -> PC1 */
-#define LEDS_GREEN     4 /**< LED3 (Green)  -> PC2 */
-#define LEDS_ORANGE    8 /**< LED4 (Orange) -> PC3 */
+#define LEDS_YELLOW             2 /**< LED2 (Yellow) -> PC1 */
+#define LEDS_GREEN              4 /**< LED3 (Green)  -> PC2 */
+#define LEDS_ORANGE             8 /**< LED4 (Orange) -> PC3 */
 
 #if USB_SERIAL_CONF_ENABLE
-#define LEDS_CONF_ALL 14
-#define LEDS_RED LEDS_ORANGE
+#define LEDS_CONF_ALL           14
+#define LEDS_RED                LEDS_ORANGE
 #else
-#define LEDS_CONF_ALL 15
-#define LEDS_RED       1 /**< LED1 (Red)    -> PC0 */
+#define LEDS_CONF_ALL           15
+#define LEDS_RED                1 /**< LED1 (Red)    -> PC0 */
 #endif
 
 /* Notify various examples that we have LEDs */
-#define PLATFORM_HAS_LEDS        1
+#define PLATFORM_HAS_LEDS       1
 /** @} */
 /*---------------------------------------------------------------------------*/
 /** \name USB configuration
  *
  * The USB pullup is driven by PC0 and is shared with LED1
  */
-#define USB_PULLUP_PORT          GPIO_C_NUM
-#define USB_PULLUP_PIN           0
+#define USB_PULLUP_PORT         GPIO_C_NUM
+#define USB_PULLUP_PIN          0
 /** @} */
 /*---------------------------------------------------------------------------*/
 /** \name UART configuration
@@ -115,17 +115,17 @@
  * UART1_* below.
  * @{
  */
-#define UART0_RX_PORT            GPIO_A_NUM
-#define UART0_RX_PIN             0
+#define UART0_RX_PORT           GPIO_A_NUM
+#define UART0_RX_PIN            0
 
-#define UART0_TX_PORT            GPIO_A_NUM
-#define UART0_TX_PIN             1
+#define UART0_TX_PORT           GPIO_A_NUM
+#define UART0_TX_PIN            1
 
-#define UART1_CTS_PORT           GPIO_B_NUM
-#define UART1_CTS_PIN            0
+#define UART1_CTS_PORT          GPIO_B_NUM
+#define UART1_CTS_PIN           0
 
-#define UART1_RTS_PORT           GPIO_D_NUM
-#define UART1_RTS_PIN            3
+#define UART1_RTS_PORT          GPIO_D_NUM
+#define UART1_RTS_PIN           3
 /** @} */
 /*---------------------------------------------------------------------------*/
 /** \name SmartRF Button configuration
@@ -139,32 +139,32 @@
  * @{
  */
 /** BUTTON_SELECT -> PA3 */
-#define BUTTON_SELECT_PORT       GPIO_A_NUM
-#define BUTTON_SELECT_PIN        3
-#define BUTTON_SELECT_VECTOR     NVIC_INT_GPIO_PORT_A
+#define BUTTON_SELECT_PORT      GPIO_A_NUM
+#define BUTTON_SELECT_PIN       3
+#define BUTTON_SELECT_VECTOR    NVIC_INT_GPIO_PORT_A
 
 /** BUTTON_LEFT -> PC4 */
-#define BUTTON_LEFT_PORT         GPIO_C_NUM
-#define BUTTON_LEFT_PIN          4
-#define BUTTON_LEFT_VECTOR       NVIC_INT_GPIO_PORT_C
+#define BUTTON_LEFT_PORT        GPIO_C_NUM
+#define BUTTON_LEFT_PIN         4
+#define BUTTON_LEFT_VECTOR      NVIC_INT_GPIO_PORT_C
 
 /** BUTTON_RIGHT -> PC5 */
-#define BUTTON_RIGHT_PORT        GPIO_C_NUM
-#define BUTTON_RIGHT_PIN         5
-#define BUTTON_RIGHT_VECTOR      NVIC_INT_GPIO_PORT_C
+#define BUTTON_RIGHT_PORT       GPIO_C_NUM
+#define BUTTON_RIGHT_PIN        5
+#define BUTTON_RIGHT_VECTOR     NVIC_INT_GPIO_PORT_C
 
 /** BUTTON_UP -> PC6 */
-#define BUTTON_UP_PORT           GPIO_C_NUM
-#define BUTTON_UP_PIN            6
-#define BUTTON_UP_VECTOR         NVIC_INT_GPIO_PORT_C
+#define BUTTON_UP_PORT          GPIO_C_NUM
+#define BUTTON_UP_PIN           6
+#define BUTTON_UP_VECTOR        NVIC_INT_GPIO_PORT_C
 
 /** BUTTON_DOWN -> PC7 */
-#define BUTTON_DOWN_PORT         GPIO_C_NUM
-#define BUTTON_DOWN_PIN          7
-#define BUTTON_DOWN_VECTOR       NVIC_INT_GPIO_PORT_C
+#define BUTTON_DOWN_PORT        GPIO_C_NUM
+#define BUTTON_DOWN_PIN         7
+#define BUTTON_DOWN_VECTOR      NVIC_INT_GPIO_PORT_C
 
 /* Notify various examples that we have Buttons */
-#define PLATFORM_HAS_BUTTON      1
+#define PLATFORM_HAS_BUTTON     1
 /** @} */
 /*---------------------------------------------------------------------------*/
 /**
@@ -176,23 +176,49 @@
  * ADC inputs can only be on port A.
  * @{
  */
-#define ADC_ALS_PWR_PORT         GPIO_A_NUM /**< ALS power GPIO control port */
-#define ADC_ALS_PWR_PIN          7 /**< ALS power GPIO control pin */
-#define ADC_ALS_OUT_PIN          6 /**< ALS output ADC input pin on port A */
+#define ADC_ALS_PWR_PORT        GPIO_A_NUM /**< ALS power GPIO control port */
+#define ADC_ALS_PWR_PIN         7 /**< ALS power GPIO control pin */
+#define ADC_ALS_OUT_PIN         6 /**< ALS output ADC input pin on port A */
 /** @} */
 /*---------------------------------------------------------------------------*/
 /**
  * \name SPI configuration
  *
- * These values configure which CC2538 pins to use for the SPI lines.
+ * These values configure which CC2538 pins to use for the SPI lines. Both
+ * SPI instances can be used independently by providing the corresponding
+ * port / pin macros.
  * @{
  */
-#define SPI_CLK_PORT             GPIO_A_NUM /**< Clock port */
-#define SPI_CLK_PIN              2          /**< Clock pin */
-#define SPI_MOSI_PORT            GPIO_A_NUM /**< MOSI port */
-#define SPI_MOSI_PIN             4          /**< MOSI pin */
-#define SPI_MISO_PORT            GPIO_A_NUM /**< MISO port */
-#define SPI_MISO_PIN             5          /**< MISO pin */
+#define SPI0_IN_USE             0
+#define SPI1_IN_USE             0
+#if SPI0_IN_USE
+/** Clock port SPI0 */
+#define SPI0_CLK_PORT           GPIO_A_NUM
+/** Clock pin SPI0 */
+#define SPI0_CLK_PIN            2
+/** TX port SPI0 (master mode: MOSI) */
+#define SPI0_TX_PORT            GPIO_A_NUM
+/** TX pin SPI0 */
+#define SPI0_TX_PIN             4
+/** RX port SPI0 (master mode: MISO */
+#define SPI0_RX_PORT            GPIO_A_NUM
+/** RX pin SPI0 */
+#define SPI0_RX_PIN             5
+#endif  /* #if SPI0_IN_USE */
+#if SPI1_IN_USE
+/** Clock port SPI1 */
+#define SPI1_CLK_PORT           GPIO_A_NUM
+/** Clock pin SPI1 */
+#define SPI1_CLK_PIN            2
+/** TX port SPI1 (master mode: MOSI) */
+#define SPI1_TX_PORT            GPIO_A_NUM
+/** TX pin SPI1 */
+#define SPI1_TX_PIN             4
+/** RX port SPI1 (master mode: MISO) */
+#define SPI1_RX_PORT            GPIO_A_NUM
+/** RX pin SPI1 */
+#define SPI1_RX_PIN             5
+#endif  /* #if SPI1_IN_USE */
 /** @} */
 /*---------------------------------------------------------------------------*/
 /**