diff --git a/drivers/atwinc15x0/atwinc15x0_bsp.c b/drivers/atwinc15x0/atwinc15x0_bsp.c
index d3d13f1f1c..aac49b00ee 100644
--- a/drivers/atwinc15x0/atwinc15x0_bsp.c
+++ b/drivers/atwinc15x0/atwinc15x0_bsp.c
@@ -83,7 +83,7 @@ void nm_bsp_register_isr(tpfNmBspIsr pfIsr)
 {
     assert(atwinc15x0);
 
-    DEBUG("%s %p\n", __func__, pfIsr);
+    DEBUG("%s %p\n", __func__, (void *)(uintptr_t)pfIsr);
 
     atwinc15x0->bsp_isr = pfIsr;
 }
diff --git a/drivers/atwinc15x0/atwinc15x0_netdev.c b/drivers/atwinc15x0/atwinc15x0_netdev.c
index a541575d59..0cca439527 100644
--- a/drivers/atwinc15x0/atwinc15x0_netdev.c
+++ b/drivers/atwinc15x0/atwinc15x0_netdev.c
@@ -345,7 +345,7 @@ static int _atwinc15x0_get(netdev_t *netdev, netopt_t opt, void *val,
     assert(dev == atwinc15x0);
 
     DEBUG("%s dev=%p opt=%u val=%p max_len=%u\n", __func__,
-          netdev, opt, val, max_len);
+          (void *)netdev, opt, val, max_len);
 
     switch (opt) {
         case NETOPT_IS_WIRED:
@@ -395,7 +395,7 @@ static int _atwinc15x0_set(netdev_t *netdev, netopt_t opt, const void *val,
     assert(val);
 
     DEBUG("%s dev=%p opt=%u val=%p max_len=%u\n", __func__,
-          netdev, opt, val, max_len);
+          (void *)netdev, opt, val, max_len);
 
     switch (opt) {
         case NETOPT_ADDRESS:
@@ -415,7 +415,7 @@ static int _atwinc15x0_init(netdev_t *netdev)
     assert(dev);
     assert(dev == atwinc15x0);
 
-    DEBUG("%s dev=%p\n", __func__, dev);
+    DEBUG("%s dev=%p\n", __func__, (void *)dev);
 
     atwinc15x0->bsp_isr = NULL;
     atwinc15x0->bsp_irq_enabled = true;
@@ -492,7 +492,7 @@ static void _atwinc15x0_isr(netdev_t *netdev)
     assert(dev);
     assert(dev == atwinc15x0);
 
-    DEBUG("%s dev=%p\n", __func__, dev);
+    DEBUG("%s dev=%p\n", __func__, (void *)dev);
 
     /* handle pending ATWINC15x0 module events */
     while (m2m_wifi_handle_events(NULL) != M2M_SUCCESS) { }
diff --git a/drivers/cc110x/cc110x_settings.c b/drivers/cc110x/cc110x_settings.c
index 47241bba75..8009c1e476 100644
--- a/drivers/cc110x/cc110x_settings.c
+++ b/drivers/cc110x/cc110x_settings.c
@@ -20,7 +20,7 @@
 #include "cc110x.h"
 #include "cc110x_internal.h"
 
-const char cc110x_conf[CC110X_CONF_SIZE] = {
+const uint8_t cc110x_conf[CC110X_CONF_SIZE] = {
     /*
      * IOCFG2; default: 0x29 (CHIP_RDYn)
      * Invert GDO2: off,
@@ -327,4 +327,4 @@ const char cc110x_conf[CC110X_CONF_SIZE] = {
     0x00,   /*< RCCTRL0 */
 };
 
-const char cc110x_magic_registers[3] = { 0x88, 0x31, 0x09 };
+const uint8_t cc110x_magic_registers[3] = { 0x88, 0x31, 0x09 };
diff --git a/drivers/cc110x/include/cc110x_settings.h b/drivers/cc110x/include/cc110x_settings.h
index 5522ab1093..704d25db6a 100644
--- a/drivers/cc110x/include/cc110x_settings.h
+++ b/drivers/cc110x/include/cc110x_settings.h
@@ -38,7 +38,7 @@ extern "C" {
 /**
  * @brief   Configuration register values for CC1100/CC1101 transceivers
  */
-extern const char cc110x_conf[CC110X_CONF_SIZE];
+extern const uint8_t cc110x_conf[CC110X_CONF_SIZE];
 
 /**
  * @brief   Magic numbers to write to the TEST2, TEST1 and TEST0 configuration
@@ -51,7 +51,7 @@ extern const char cc110x_conf[CC110X_CONF_SIZE];
  * transceiver configuration, those numbers should be checked again with the
  * SmartRF Studio
  */
-extern const char cc110x_magic_registers[3];
+extern const uint8_t cc110x_magic_registers[3];
 
 /**
  * @name    Configuration data that specify the 8 available output power levels
diff --git a/drivers/encx24j600/encx24j600.c b/drivers/encx24j600/encx24j600.c
index 4429a007dc..0e158a39f6 100644
--- a/drivers/encx24j600/encx24j600.c
+++ b/drivers/encx24j600/encx24j600.c
@@ -50,7 +50,7 @@
 #define TX_BUFFER_END           (RX_BUFFER_START)
 #define TX_BUFFER_START         (TX_BUFFER_END - TX_BUFFER_LEN)
 
-static void cmd(encx24j600_t *dev, char cmd);
+static void cmd(encx24j600_t *dev, uint8_t cmd);
 static void reg_set(encx24j600_t *dev, uint8_t reg, uint16_t value);
 static uint16_t reg_get(encx24j600_t *dev, uint8_t reg);
 static void reg_clear_bits(encx24j600_t *dev, uint8_t reg, uint16_t mask);
@@ -163,8 +163,8 @@ static void phy_reg_set(encx24j600_t *dev, uint8_t reg, uint16_t value) {
     reg_set(dev, ENC_MIWR, value);
 }
 
-static void cmd(encx24j600_t *dev, char cmd) {
-    spi_transfer_byte(dev->spi, dev->cs, false, (uint8_t)cmd);
+static void cmd(encx24j600_t *dev, uint8_t cmd) {
+    spi_transfer_byte(dev->spi, dev->cs, false, cmd);
 }
 
 static void cmdn(encx24j600_t *dev, uint8_t cmd, char *out, char *in, int len) {
diff --git a/drivers/include/cc110x.h b/drivers/include/cc110x.h
index 4c3856d91d..532d6407a2 100644
--- a/drivers/include/cc110x.h
+++ b/drivers/include/cc110x.h
@@ -261,13 +261,13 @@ extern "C" {
  * page 31 in the data sheet for the possible states in the status byte.
  */
 typedef enum {
-    CC110X_STATE_IDLE               = 0b00000000,   /**< IDLE state */
+    CC110X_STATE_IDLE               = 0x00,   /**< IDLE state */
     /**
      * @brief   Frame received, waiting for upper layer to retrieve it
      *
      * Transceiver is in IDLE state.
      */
-    CC110X_STATE_FRAME_READY        = 0b00001000,
+    CC110X_STATE_FRAME_READY        = 0x08,
     /**
      * @brief   Frame received, waiting for upper layer to retrieve it
      *
@@ -276,26 +276,26 @@ typedef enum {
      * bring it in the IDLE state. Thus, we set the three least significant bits
      * to the IDLE state
      */
-    CC110X_STATE_OFF                = 0b00010000,
-    CC110X_STATE_RX_MODE            = 0b00000001,   /**< Listening for frames */
+    CC110X_STATE_OFF                = 0x10,
+    CC110X_STATE_RX_MODE            = 0x01,   /**< Listening for frames */
     /**
      * @brief   Receiving a frame just now
      *
      * Transceiver is in RX state.
      */
-    CC110X_STATE_RECEIVING          = 0b00001001,
-    CC110X_STATE_TX_MODE            = 0b00000010,   /**< Transmit mode */
+    CC110X_STATE_RECEIVING          = 0x09,
+    CC110X_STATE_TX_MODE            = 0x02,   /**< Transmit mode */
     /**
      * @brief   Waiting for transceiver to complete outgoing transmission
      *
      * Transceiver is in TX state
      */
-    CC110X_STATE_TX_COMPLETING      = 0b00001010,
-    CC110X_STATE_FSTXON             = 0b00000011,   /**< Fast TX ready */
-    CC110X_STATE_CALIBRATE          = 0b00000100,   /**< Device is calibrating */
-    CC110X_STATE_SETTLING           = 0b00000101,   /**< PLL is settling */
-    CC110X_STATE_RXFIFO_OVERFLOW    = 0b00000110,   /**< RX FIFO overflown */
-    CC110X_STATE_TXFIFO_UNDERFLOW   = 0b00000111,   /**< TX FIFO underflown */
+    CC110X_STATE_TX_COMPLETING      = 0x0A,
+    CC110X_STATE_FSTXON             = 0x03,   /**< Fast TX ready */
+    CC110X_STATE_CALIBRATE          = 0x04,   /**< Device is calibrating */
+    CC110X_STATE_SETTLING           = 0x05,   /**< PLL is settling */
+    CC110X_STATE_RXFIFO_OVERFLOW    = 0x06,   /**< RX FIFO overflown */
+    CC110X_STATE_TXFIFO_UNDERFLOW   = 0x07,   /**< TX FIFO underflown */
 } cc110x_state_t;
 
 /**
diff --git a/drivers/include/nrf24l01p.h b/drivers/include/nrf24l01p.h
index de7ffb47fe..3dfb2294bf 100644
--- a/drivers/include/nrf24l01p.h
+++ b/drivers/include/nrf24l01p.h
@@ -340,7 +340,7 @@ int nrf24l01p_set_payload_width(const nrf24l01p_t *dev,
 * @return           Address length on success.
 * @return           -1 on error.
 */
-int nrf24l01p_set_tx_address(const nrf24l01p_t *dev, const char *saddr, unsigned int length);
+int nrf24l01p_set_tx_address(const nrf24l01p_t *dev, const uint8_t *saddr, unsigned int length);
 
 /**
 * @brief   Set the TX address for the nrf24l01+ transceiver (long int).
@@ -370,7 +370,7 @@ int nrf24l01p_set_tx_address_long(const nrf24l01p_t *dev, uint64_t saddr, unsign
 * @return           Address length on success.
 * @return           -1 on error.
 */
-int nrf24l01p_set_rx_address(const nrf24l01p_t *dev, nrf24l01p_rx_pipe_t pipe, const char *saddr, unsigned int length);
+int nrf24l01p_set_rx_address(const nrf24l01p_t *dev, nrf24l01p_rx_pipe_t pipe, const uint8_t *saddr, unsigned int length);
 
 /**
 * @brief   Set the RX address for the nrf24l01+ transceiver (long int).
diff --git a/drivers/kw2xrf/include/overwrites.h b/drivers/kw2xrf/include/overwrites.h
index 817ed8e095..c81426ce21 100644
--- a/drivers/kw2xrf/include/overwrites.h
+++ b/drivers/kw2xrf/include/overwrites.h
@@ -39,8 +39,8 @@ extern "C" {
 #endif
 
 typedef struct overwrites_tag {
-    char address;
-    char data;
+    uint8_t address;
+    uint8_t data;
 } overwrites_t;
 
 
diff --git a/drivers/nrf24l01p/nrf24l01p.c b/drivers/nrf24l01p/nrf24l01p.c
index 515e2b7db2..27c13085db 100644
--- a/drivers/nrf24l01p/nrf24l01p.c
+++ b/drivers/nrf24l01p/nrf24l01p.c
@@ -65,8 +65,8 @@ int nrf24l01p_write_reg(const nrf24l01p_t *dev, char reg, char write)
 int nrf24l01p_init(nrf24l01p_t *dev, spi_t spi, gpio_t ce, gpio_t cs, gpio_t irq)
 {
     int status;
-    static const char INITIAL_TX_ADDRESS[] =  {0xe7, 0xe7, 0xe7, 0xe7, 0xe7,};
-    static const char INITIAL_RX_ADDRESS[] =  {0xe7, 0xe7, 0xe7, 0xe7, 0xe7,};
+    static const uint8_t INITIAL_TX_ADDRESS[] =  {0xe7, 0xe7, 0xe7, 0xe7, 0xe7,};
+    static const uint8_t INITIAL_RX_ADDRESS[] =  {0xe7, 0xe7, 0xe7, 0xe7, 0xe7,};
 
     dev->spi = spi;
     dev->ce = ce;
@@ -363,7 +363,7 @@ int nrf24l01p_set_payload_width(const nrf24l01p_t *dev,
 
 
 
-int nrf24l01p_set_tx_address(const nrf24l01p_t *dev, const char *saddr, unsigned int length)
+int nrf24l01p_set_tx_address(const nrf24l01p_t *dev, const uint8_t *saddr, unsigned int length)
 {
     /* Acquire exclusive access to the bus. */
     spi_acquire(dev->spi, dev->cs, SPI_MODE, SPI_CLK);
@@ -427,7 +427,7 @@ uint64_t nrf24l01p_get_tx_address_long(const nrf24l01p_t *dev)
 }
 
 
-int nrf24l01p_set_rx_address(const nrf24l01p_t *dev, nrf24l01p_rx_pipe_t pipe, const char *saddr, unsigned int length)
+int nrf24l01p_set_rx_address(const nrf24l01p_t *dev, nrf24l01p_rx_pipe_t pipe, const uint8_t *saddr, unsigned int length)
 {
     char pipe_addr;
 
@@ -477,7 +477,7 @@ int nrf24l01p_set_rx_address(const nrf24l01p_t *dev, nrf24l01p_rx_pipe_t pipe, c
 
 int nrf24l01p_set_rx_address_long(const nrf24l01p_t *dev, nrf24l01p_rx_pipe_t pipe, uint64_t saddr, unsigned int length)
 {
-    char buf[length];
+    uint8_t buf[length];
 
     if (length <= INITIAL_ADDRESS_WIDTH) {
         for (unsigned int i = 0; i < length; i++) {
diff --git a/pkg/driver_atwinc15x0/Makefile b/pkg/driver_atwinc15x0/Makefile
index ab84af721d..749c398075 100644
--- a/pkg/driver_atwinc15x0/Makefile
+++ b/pkg/driver_atwinc15x0/Makefile
@@ -14,6 +14,8 @@ CFLAGS += -Wno-incompatible-pointer-types-discards-qualifiers
 CFLAGS += -DETH_MODE
 CFLAGS += -I$(PKG_SOURCE_DIR)/src
 
+CFLAGS += -Wno-pedantic
+
 all:
 	"$(MAKE)" -C $(PKG_SOURCE_DIR)/src/driver/source -f $(RIOTBASE)/Makefile.base MODULE=driver_atwinc15x0
 	"$(MAKE)" -C $(PKG_SOURCE_DIR)/src/common/source -f $(RIOTBASE)/Makefile.base MODULE=driver_atwinc15x0_common
diff --git a/pkg/semtech-loramac/contrib/semtech_loramac.c b/pkg/semtech-loramac/contrib/semtech_loramac.c
index 97c6e5055c..0cd3a46b4f 100644
--- a/pkg/semtech-loramac/contrib/semtech_loramac.c
+++ b/pkg/semtech-loramac/contrib/semtech_loramac.c
@@ -609,7 +609,7 @@ void *_semtech_loramac_event_loop(void *arg)
                 case MSG_TYPE_MAC_TIMEOUT:
                 {
                     DEBUG("[semtech-loramac] MAC timer timeout\n");
-                    void (*callback)(void) = msg.content.ptr;
+                    void (*callback)(void) = (void (*)(void))(uintptr_t)msg.content.value;
                     callback();
                     break;
                 }
diff --git a/pkg/semtech-loramac/contrib/semtech_loramac_timer.c b/pkg/semtech-loramac/contrib/semtech_loramac_timer.c
index c77b24d5b4..d1ed507407 100644
--- a/pkg/semtech-loramac/contrib/semtech_loramac_timer.c
+++ b/pkg/semtech-loramac/contrib/semtech_loramac_timer.c
@@ -44,7 +44,7 @@ void TimerStart(TimerEvent_t *obj)
     xtimer_t *timer = &(obj->dev);
     msg_t *msg = &(obj->msg);
     msg->type = MSG_TYPE_MAC_TIMEOUT;
-    msg->content.ptr = obj->cb;
+    msg->content.value = (uintptr_t)obj->cb;
     xtimer_set_msg(timer, obj->timeout, msg, semtech_loramac_pid);
 }