diff --git a/src/application/spi/main.cc b/src/application/spi/main.cc
index 421af2b..952e271 100644
--- a/src/application/spi/main.cc
+++ b/src/application/spi/main.cc
@@ -9,7 +9,9 @@ const uint8_t buf[] = "Test";
 int main(void)
 {
     Gpio led_1(17);
-    Spi spi_0(0, 2, 3, 4, 25);
+    Gpio lcd_chip_select(25);
+
+    Spi spi_0(0, 2, 3, 4, lcd_chip_select);
 
     while(1) {
         delay_ms(200);
diff --git a/src/application/st7789_lcd/main.cc b/src/application/st7789_lcd/main.cc
index 5ddb003..9afbbab 100644
--- a/src/application/st7789_lcd/main.cc
+++ b/src/application/st7789_lcd/main.cc
@@ -3,17 +3,22 @@
 #include "platform/hal.h"
 #include "st7789.h"
 
+hal::Gpio led_1(17);
+
 hal::Gpio lcd_reset(26);
 hal::Gpio lcd_data_command(18);
 hal::Gpio lcd_backlight(23);
 hal::Gpio lcd_chip_select(25);
-hal::Spi lcd_spi(0, 2, 3, 4, 25);
+hal::Spi lcd_spi(0, 2, 3, 4, lcd_chip_select);
 
-St7789 lcd(lcd_spi, lcd_reset, lcd_data_command, lcd_backlight, lcd_chip_select);
+St7789 lcd(lcd_spi, lcd_reset, lcd_data_command, lcd_backlight);
 
 int main(void)
 {
+    lcd.init();
+    lcd.clear(0);
     while(true) {
         delay_ms(200);
+        led_1.toggle();
     }
 }
diff --git a/src/platform/nrf52/spi.cc b/src/platform/nrf52/spi.cc
index 19cf22c..21a920d 100644
--- a/src/platform/nrf52/spi.cc
+++ b/src/platform/nrf52/spi.cc
@@ -12,7 +12,8 @@ extern "C" {
 
 using namespace platform::nrf52;
 
-Spi::Spi(uint32_t instance, uint32_t sck, uint32_t mosi, uint32_t miso, uint32_t cs)
+Spi::Spi(uint32_t instance, uint32_t sck, uint32_t mosi, uint32_t miso, interfaces::GpioInterface & cs)
+    : chip_select(cs)
 {
     assert(instance < 3);
 
@@ -24,6 +25,8 @@ Spi::Spi(uint32_t instance, uint32_t sck, uint32_t mosi, uint32_t miso, uint32_t
         SPI_REGS = reinterpret_cast<NRF_SPI_Type *>(NRF_SPI2_BASE);
     }
 
+    this->chip_select.set();
+
     SPI_REGS->ENABLE = 0;
     SPI_REGS->PSELSCK = sck;
     SPI_REGS->PSELMOSI = mosi;
@@ -41,13 +44,11 @@ Spi::~Spi()
 
 void Spi::send(const uint8_t * buffer, uint32_t len)
 {
-    //FIXME: missing CS handling
-
+    this->chip_select.clear();
     for(unsigned int i = 0; i < len; i++) {
         this->transfer(buffer[i]);
     }
-
-    //FIXME: missing CS handling
+    this->chip_select.set();
 }
 
 void Spi::recv(uint8_t * buffer, uint32_t len)
diff --git a/src/platform/nrf52/spi.h b/src/platform/nrf52/spi.h
index d236f4e..51913c4 100644
--- a/src/platform/nrf52/spi.h
+++ b/src/platform/nrf52/spi.h
@@ -1,6 +1,7 @@
 #ifndef __PLATFORM_NRF52_SPI_H__
 #define __PLATFORM_NRF52_SPI_H__
 
+#include "gpio_interface.h"
 #include "spi_interface.h"
 
 namespace platform::nrf52 {
@@ -8,13 +9,15 @@ namespace platform::nrf52 {
 class Spi : public interfaces::SpiInterface
 {
 public:
-    Spi(uint32_t instance, uint32_t sck, uint32_t mosi, uint32_t miso, uint32_t cs);
+    Spi(uint32_t instance, uint32_t sck, uint32_t mosi, uint32_t miso, interfaces::GpioInterface & cs);
     ~Spi();
     void send(const uint8_t * buffer, uint32_t len) override;
     void recv(uint8_t * buffer, uint32_t len) override;
 
 private:
     uint32_t transfer(uint32_t);
+
+    interfaces::GpioInterface & chip_select;
 };
 
 }
diff --git a/src/st7789.cc b/src/st7789.cc
index 9468d14..d7f1059 100644
--- a/src/st7789.cc
+++ b/src/st7789.cc
@@ -6,27 +6,21 @@
 St7789::St7789(interfaces::SpiInterface & spi_if,
                interfaces::GpioInterface & rst,
                interfaces::GpioInterface & dc,
-               interfaces::GpioInterface & bl,
-               interfaces::GpioInterface & cs)
+               interfaces::GpioInterface & bl)
     : spi(spi_if)
     , reset(rst)
     , data_command(dc)
     , backlight(bl)
-    , select(cs)
 {
     this->reset.set();
     this->data_command.set();
     this->backlight.set();
-    this->select.clear();
 
     // hard reset
     this->reset.clear();
     delay_ms(100);
     this->reset.set();
     delay_ms(100);
-
-    this->init();
-    this->clear(0x0000);
 }
 
 void St7789::init()
diff --git a/src/st7789.h b/src/st7789.h
index ba97bfd..7e9e94a 100644
--- a/src/st7789.h
+++ b/src/st7789.h
@@ -9,22 +9,21 @@ class St7789
 {
 public:
     St7789(interfaces::SpiInterface &,
-           interfaces::GpioInterface &,
            interfaces::GpioInterface &,
            interfaces::GpioInterface &,
            interfaces::GpioInterface &);
 
+    void init();
+    void clear(uint16_t Color);
+
 private:
     interfaces::SpiInterface & spi;
     interfaces::GpioInterface & reset;
     interfaces::GpioInterface & data_command;
     interfaces::GpioInterface & backlight;
-    interfaces::GpioInterface & select;
 
-    void init();
     void send_cmd(uint8_t);
     void send_data(uint8_t);
-    void clear(uint16_t Color);
     void set_windows(uint16_t x_start, uint16_t y_start, uint16_t x_end, uint16_t y_end);
 };