Add virtual timer

.vscode/tasks.json

@@ -2,10 +2,9 @@
     "version": "2.0.0",
     "options": {
         "env": {
-            // "APPLICATION": "blinky",
+            "APPLICATION": "blinky",
             // "APPLICATION": "spi",
             // "APPLICATION": "st7789_lcd",
-            "APPLICATION": "sys_tick",
         },
     },
     "presentation": {

Makefile

@@ -33,6 +33,7 @@ CC_SRCS = $(wildcard $(SRC_DIR)/*.cc)
 CC_SRCS += $(wildcard $(SRC_DIR)/platform/$(CORE)/*.cc)
 CC_SRCS += $(wildcard $(SRC_DIR)/platform/$(PLATFORM)/*.cc)
 CC_SRCS += $(wildcard $(SRC_DIR)/application/$(APPLICATION)/*.cc)
+CC_SRCS += $(wildcard $(SRC_DIR)/virtual_timer/*.cc)
 CC_OBJS = $(patsubst $(SRC_DIR)%,$(OBJ_DIR)%,$(patsubst %.cc,%.cc.o,$(CC_SRCS)))
 
 OBJS = $(A_OBJS) $(C_OBJS) $(CC_OBJS)

interfaces/HwTimerInterface.h

@@ -0,0 +1,19 @@
+#ifndef __INTERFACES_HWTIMERINTERFACE_H__
+#define __INTERFACES_HWTIMERINTERFACE_H__
+
+#include <cstdint>
+
+namespace pinetime::interfaces
+{
+
+class HwTimerInterface
+{
+public:
+    virtual void enable_timer() = 0;
+    virtual void disable_timer() = 0;
+    virtual uint64_t tick() = 0;
+};
+
+}
+
+#endif

interfaces/VirtualTimerInterface.h

@@ -0,0 +1,19 @@
+#ifndef __INTERFACES_VIRTUALTIMERINTERFACE_H__
+#define __INTERFACES_VIRTUALTIMERINTERFACE_H__
+
+#include <cstdint>
+
+namespace pinetime::interfaces
+{
+
+class VirtualTimerInterface
+{
+public:
+    virtual void timer_notification(uint64_t) = 0;
+    virtual void timer_enable() = 0;
+    virtual void timer_disable() = 0;
+};
+
+}
+
+#endif

src/Pool.h

@@ -0,0 +1,56 @@
+#ifndef __POOL_H__
+#define __POOL_H__
+
+#include <cstddef>
+#include <cstdint>
+
+#include "platform/cm4/InterruptLock.h"
+
+namespace pinetime
+{
+
+template <typename T, std::size_t sizeT>
+class Pool
+{
+    union Item
+    {
+        uint8_t item[sizeof(T)];
+        Item * next;
+    };
+    Item items[sizeT];
+    uint8_t map[sizeT];
+
+public:
+    Pool()
+    {
+        for(unsigned int i = 0; i < sizeT; i++) {
+            map[i] = 0;
+        }
+    }
+
+    void *alloc()
+    {
+        pinetime::platform::cm4::InterruptLock lock;
+        void * res = nullptr;
+        for(unsigned int i = 0; i < sizeT; i++) {
+            if(map[i] == 0) {
+                map[i] = 0xff;
+                res = static_cast<void *>(items + i);
+                break;
+            }
+        }
+        return res;
+    }
+
+    void free(T * ptr)
+    {
+        pinetime::platform::cm4::InterruptLock lock;
+        // ptr is not assumed to be aligned, since the integer based aritmetic provides always the correct index and omits the ramainder.
+        std::size_t index = (reinterpret_cast<std::uintptr_t>(ptr) - reinterpret_cast<std::uintptr_t>(items)) / sizeof(Item);
+        map[index] = 0;
+    }
+};
+
+}
+
+#endif

src/application/blinky/main.cc

@@ -1,15 +1,19 @@
 #include <array>
 
-#include "delay.h"
+#include "virtual_timer/VirtualTimerDistributor.h"
 
 #include "platform/cm4/InterruptHandler.h"
 #include "platform/cm4/InterruptGuardian.h"
+#include "platform/cm4/SystemTick.h"
 
 #include "platform/nrf52/gpio.h"
 #include "platform/nrf52/InterruptHandler.h"
 #include "platform/nrf52/InterruptGuardian.h"
 
+#include "delay.h"
+
 using namespace pinetime::platform;
+using namespace pinetime::virtual_timer;
 
 enum {
     PIN_NUMBER_LED_1 = 17,
@@ -18,23 +22,30 @@ enum {
     PIN_NUMBER_LED_4 = 20
 };
 
+// LEDs
 nrf52::Gpio led_1(PIN_NUMBER_LED_1);
 nrf52::Gpio led_2(PIN_NUMBER_LED_2);
 nrf52::Gpio led_3(PIN_NUMBER_LED_3);
 nrf52::Gpio led_4(PIN_NUMBER_LED_4);
-
 std::array<nrf52::Gpio *, 4> leds = {&led_1, &led_2, &led_3, &led_4};
 
-cm4::InterruptGuardian cm4::InterruptGuardian::instance;
+// IRQs
 nrf52::InterruptGuardian nrf52::InterruptGuardian::instance;
+cm4::InterruptGuardian cm4::InterruptGuardian::instance;
+
+// Timer
+cm4::SystemTick system_tick;
+VirtualTimerDistributor virtual_timer_distributor(system_tick.instance());
+pinetime::Delay delay;
 
 int main(void)
 {
+    cm4::InterruptGuardian::enable_interrupts();
     while(true) {
         for(auto it = std::begin(leds); it != std::end(leds); ++it) {
             nrf52::Gpio * tmp = *it;
             tmp->toggle();
-            delay_ms(500);
+            delay.delay(200);
         }
     }
     return 0;

src/application/spi/main.cc

@@ -1,6 +1,4 @@
 
-#include "delay.h"
-
 #include "platform/cm4/InterruptHandler.h"
 #include "platform/cm4/InterruptGuardian.h"
 
@@ -11,19 +9,19 @@
 
 using namespace pinetime::platform;
 
-const uint8_t buf[] = "Test";
+uint8_t buf[] = "Test";
 
 nrf52::Gpio led_1(17);
 nrf52::Gpio lcd_chip_select(25);
-nrf52::Spi spi_0(0, 2, 3, 4, lcd_chip_select);
 
 cm4::InterruptGuardian cm4::InterruptGuardian::instance;
 nrf52::InterruptGuardian nrf52::InterruptGuardian::instance;
 
 int main(void)
 {
+    cm4::InterruptGuardian::enable_interrupts();
+    nrf52::Spi spi_0(0, 2, 3, 4, lcd_chip_select);
     while(1) {
-        delay_ms(200);
         spi_0.send(buf, sizeof(buf));
         led_1.toggle();
     }

src/application/st7789_lcd/main.cc

@@ -1,5 +1,3 @@
-#include "delay.h"
-
 #include "platform/cm4/InterruptHandler.h"
 #include "platform/cm4/InterruptGuardian.h"
 
@@ -26,10 +24,10 @@ nrf52::InterruptGuardian nrf52::InterruptGuardian::instance;
 
 int main(void)
 {
+    cm4::InterruptGuardian::enable_interrupts();
     lcd.init();
     lcd.clear(0);
     while(true) {
-        delay_ms(200);
         led_1.toggle();
     }
 }

src/application/sys_tick/main.cc

@@ -1,49 +0,0 @@
-#include <array>
-
-#include "platform/cm4/InterruptHandler.h"
-#include "platform/cm4/InterruptGuardian.h"
-#include "platform/cm4/SystemTick.h"
-
-#include "platform/nrf52/gpio.h"
-#include "platform/nrf52/InterruptHandler.h"
-#include "platform/nrf52/InterruptGuardian.h"
-
-using namespace pinetime::platform;
-
-enum {
-    PIN_NUMBER_LED_1 = 17,
-    PIN_NUMBER_LED_2 = 18,
-    PIN_NUMBER_LED_3 = 19,
-    PIN_NUMBER_LED_4 = 20
-};
-
-nrf52::Gpio led_1(PIN_NUMBER_LED_1);
-nrf52::Gpio led_2(PIN_NUMBER_LED_2);
-nrf52::Gpio led_3(PIN_NUMBER_LED_3);
-nrf52::Gpio led_4(PIN_NUMBER_LED_4);
-
-std::array<nrf52::Gpio *, 4> leds = {&led_1, &led_2, &led_3, &led_4};
-
-nrf52::InterruptGuardian nrf52::InterruptGuardian::instance;
-cm4::InterruptGuardian cm4::InterruptGuardian::instance;
-
-
-int main(void)
-{
-    cm4::SystemTick ticker;
-    ticker.enable();
-    uint32_t last_tick = 0;
-
-    cm4::InterruptGuardian::enable_interrupts();
-    while(true) {
-        for(auto it = std::begin(leds); it != std::end(leds); ++it) {
-            volatile uint32_t tick = ticker.tick() / 1000;
-            if(tick != last_tick) {
-                nrf52::Gpio * tmp = *it;
-                tmp->toggle();
-                last_tick = tick;
-            }
-        }
-    }
-    return 0;
-}

src/delay.cc

@@ -0,0 +1,27 @@
+#include "delay.h"
+
+using namespace pinetime;
+using namespace pinetime::virtual_timer;
+
+Delay::Delay()
+    : VirtualTimer(0)
+    , pause(false)
+{
+}
+
+void Delay::delay(uint64_t time_ms)
+{
+    this->pause = true;
+    this->timer_set_period_ms(time_ms);
+    this->timer_enable();
+    while(this->pause) {
+        // FIXME: Low power
+        asm volatile("nop");
+    }
+    this->timer_disable();
+}
+
+void Delay::notification()
+{
+    this->pause = false;
+}

src/delay.h

@@ -0,0 +1,25 @@
+#ifndef __DELAY_H__
+#define __DELAY_H__
+
+#include "virtual_timer/VirtualTimer.h"
+
+namespace pinetime
+{
+
+class Delay
+    : public pinetime::virtual_timer::VirtualTimer
+{
+
+public:
+    Delay();
+    void delay(uint64_t);
+
+    void notification();
+
+private:
+    bool pause;
+};
+
+}
+
+#endif

src/platform/cm4/SystemTick.cc

@@ -2,11 +2,13 @@ extern "C" {
     #include "nrf52.h"
 }
 
+#include "virtual_timer/VirtualTimerDistributor.h"
 #include "platform/cm4/InterruptHandler.h"
 #include "platform/cm4/InterruptGuardian.h"
 #include "platform/cm4/SystemTick.h"
 
 using namespace pinetime::platform::cm4;
+using namespace pinetime::virtual_timer;
 
 SystemTick::SystemTick()
     : InterruptHandler(InterruptGuardian::Cm4IrqN::SYS_TICK_IRQ)
@@ -17,19 +19,20 @@ SystemTick::SystemTick()
 void SystemTick::handle()
 {
     this->sys_tick++;
+    VirtualTimerDistributor::instance().notify(this->sys_tick);
 }
 
-void SystemTick::enable()
+void SystemTick::enable_timer()
 {
     SysTick_Config(SystemCoreClock / 1000);
 }
 
-void SystemTick::disable()
+void SystemTick::disable_timer()
 {
     SysTick->CTRL = 0;
 }
 
-uint32_t SystemTick::tick()
+uint64_t SystemTick::tick()
 {
     return this->sys_tick;
 }

src/platform/cm4/SystemTick.h

@@ -1,21 +1,34 @@
 #ifndef __PLATFORM_CM4_SYSTEMTICK_H__
 #define __PLATFORM_CM4_SYSTEMTICK_H__
 
+#include "HwTimerInterface.h"
 #include "platform/cm4/InterruptHandler.h"
 
-namespace pinetime::platform::cm4 {
+namespace pinetime::platform::cm4
+{
+class SystemTick;
+}
+extern pinetime::platform::cm4::SystemTick system_tick;
 
-class SystemTick : public pinetime::platform::cm4::InterruptHandler
+namespace pinetime::platform::cm4
+{
+class SystemTick
+    : public pinetime::platform::cm4::InterruptHandler
+    , public pinetime::interfaces::HwTimerInterface
 {
     public:
         SystemTick();
-        void handle();
-        void enable();
-        void disable();
-        uint32_t tick();
+
+        static inline SystemTick & instance() { return system_tick; }
+
+        void enable_timer() override;
+        void disable_timer() override;
+        uint64_t tick() override;
+
+        void handle() override;
 
     private:
-        uint32_t sys_tick;
+        uint64_t sys_tick;
 };
 
 }

src/platform/nrf52/InterruptGuardian.h

@@ -15,43 +15,43 @@ public:
     InterruptGuardian();
 
     enum Nrf52IrqN {
-        POWER_CLOCK_IRQn,                       //!< 0 POWER_CLOCK
-        RADIO_IRQn,                             //!< 1 RADIO
-        UARTE0_UART0_IRQn,                      //!< 2 UARTE0_UART0
-        SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQn, //!< 3 SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0
-        SPIM1_SPIS1_TWIM1_TWIS1_SPI1_TWI1_IRQn, //!< 4 SPIM1_SPIS1_TWIM1_TWIS1_SPI1_TWI1
-        NFCT_IRQn,                              //!< 5 NFCT
-        GPIOTE_IRQn,                            //!< 6  GPIOTE
-        SAADC_IRQn,                             //!< 7  SAADC
-        TIMER0_IRQn,                            //!< 8  TIMER0
-        TIMER1_IRQn,                            //!< 9  TIMER1
-        TIMER2_IRQn,                            //!< 10 TIMER2
-        RTC0_IRQn,                              //!< 11 RTC0
-        TEMP_IRQn,                              //!< 12 TEMP
-        RNG_IRQn,                               //!< 13 RNG
-        ECB_IRQn,                               //!< 14 ECB
-        CCM_AAR_IRQn,                           //!< 15 CCM_AAR
-        WDT_IRQn,                               //!< 16 WDT
-        RTC1_IRQn,                              //!< 17 RTC1
-        QDEC_IRQn,                              //!< 18 QDEC
-        COMP_LPCOMP_IRQn,                       //!< 19 COMP_LPCOMP
-        SWI0_EGU0_IRQn,                         //!< 20 SWI0_EGU0
-        SWI1_EGU1_IRQn,                         //!< 21 SWI1_EGU1
-        SWI2_EGU2_IRQn,                         //!< 22 SWI2_EGU2
-        SWI3_EGU3_IRQn,                         //!< 23 SWI3_EGU3
-        SWI4_EGU4_IRQn,                         //!< 24 SWI4_EGU4
-        SWI5_EGU5_IRQn,                         //!< 25 SWI5_EGU5
-        TIMER3_IRQn,                            //!< 26 TIMER3
-        TIMER4_IRQn,                            //!< 27 TIMER4
-        PWM0_IRQn,                              //!< 28 PWM0
-        PDM_IRQn,                               //!< 29 PDM
-        MWU_IRQn,                               //!< 32 MWU
-        PWM1_IRQn,                              //!< 33 PWM1
-        PWM2_IRQn,                              //!< 34 PWM2
-        SPIM2_SPIS2_SPI2_IRQn,                  //!< 35 SPIM2_SPIS2_SPI2
-        RTC2_IRQn,                              //!< 36 RTC2
-        I2S_IRQn,                               //!< 37 I2S
-        FPU_IRQn                                //!< 38 FPU
+        POWER_CLOCK_IRQ,                       //!< 0 POWER_CLOCK
+        RADIO_IRQ,                             //!< 1 RADIO
+        UARTE0_UART0_IRQ,                      //!< 2 UARTE0_UART0
+        SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQ, //!< 3 SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0
+        SPIM1_SPIS1_TWIM1_TWIS1_SPI1_TWI1_IRQ, //!< 4 SPIM1_SPIS1_TWIM1_TWIS1_SPI1_TWI1
+        NFCT_IRQ,                              //!< 5 NFCT
+        GPIOTE_IRQ,                            //!< 6  GPIOTE
+        SAADC_IRQ,                             //!< 7  SAADC
+        TIMER0_IRQ,                            //!< 8  TIMER0
+        TIMER1_IRQ,                            //!< 9  TIMER1
+        TIMER2_IRQ,                            //!< 10 TIMER2
+        RTC0_IRQ,                              //!< 11 RTC0
+        TEMP_IRQ,                              //!< 12 TEMP
+        RNG_IRQ,                               //!< 13 RNG
+        ECB_IRQ,                               //!< 14 ECB
+        CCM_AAR_IRQ,                           //!< 15 CCM_AAR
+        WDT_IRQ,                               //!< 16 WDT
+        RTC1_IRQ,                              //!< 17 RTC1
+        QDEC_IRQ,                              //!< 18 QDEC
+        COMP_LPCOMP_IRQ,                       //!< 19 COMP_LPCOMP
+        SWI0_EGU0_IRQ,                         //!< 20 SWI0_EGU0
+        SWI1_EGU1_IRQ,                         //!< 21 SWI1_EGU1
+        SWI2_EGU2_IRQ,                         //!< 22 SWI2_EGU2
+        SWI3_EGU3_IRQ,                         //!< 23 SWI3_EGU3
+        SWI4_EGU4_IRQ,                         //!< 24 SWI4_EGU4
+        SWI5_EGU5_IRQ,                         //!< 25 SWI5_EGU5
+        TIMER3_IRQ,                            //!< 26 TIMER3
+        TIMER4_IRQ,                            //!< 27 TIMER4
+        PWM0_IRQ,                              //!< 28 PWM0
+        PDM_IRQ,                               //!< 29 PDM
+        MWU_IRQ,                               //!< 32 MWU
+        PWM1_IRQ,                              //!< 33 PWM1
+        PWM2_IRQ,                              //!< 34 PWM2
+        SPIM2_SPIS2_SPI2_IRQ,                  //!< 35 SPIM2_SPIS2_SPI2
+        RTC2_IRQ,                              //!< 36 RTC2
+        I2S_IRQ,                               //!< 37 I2S
+        FPU_IRQ                                //!< 38 FPU
     };
 
 private:

src/platform/nrf52/low_level_interrupt.cc

@@ -44,3 +44,13 @@ extern "C" {
 }
 
 using namespace pinetime::platform::nrf52;
+
+void SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQHandler(void)
+{
+    uint32_t irq_nr = InterruptGuardian::Nrf52IrqN::SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQ;
+    InterruptHandler *h = InterruptGuardian::instance.nrf52_vector[irq_nr];
+
+    assert(h != nullptr);
+
+    h->handle();
+}

src/platform/nrf52/spi.cc

@@ -1,70 +1,130 @@
 #include <assert.h>
 
+#include "platform/nrf52/InterruptHandler.h"
+#include "platform/nrf52/InterruptGuardian.h"
+
 #include "platform/nrf52/spi.h"
 
 extern "C" {
     #include "nrf52.h"
     #include "nrf52_bitfields.h"
 
-    NRF_SPI_Type *SPI_REGS = reinterpret_cast<NRF_SPI_Type *>(NRF_SPI0_BASE);
+    NRF_GPIO_Type *const GPIO_REGS = reinterpret_cast<NRF_GPIO_Type *>(NRF_P0_BASE);
+    NRF_SPIM_Type *SPIM_REGS = reinterpret_cast<NRF_SPIM_Type *>(NRF_SPIM0_BASE);
 }
 
 using namespace pinetime::platform::nrf52;
 
 Spi::Spi(uint32_t instance, uint32_t sck, uint32_t mosi, uint32_t miso, pinetime::interfaces::GpioInterface & cs)
-    : chip_select(cs)
+    : InterruptHandler(InterruptGuardian::Nrf52IrqN::SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQ)
+    , chip_select(cs)
+    , xfer_active(false)
 {
     assert(instance < 3);
 
-    if(instance == 0) {
-        SPI_REGS = reinterpret_cast<NRF_SPI_Type *>(NRF_SPI0_BASE);
+    // sck pin
+    GPIO_REGS->OUTCLR = 1UL << sck;
+    GPIO_REGS->PIN_CNF[mosi] = GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos
+                             | GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos
+                             | GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos
+                             | GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos
+                             | GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos;
+    // mosi pin
+    GPIO_REGS->OUTCLR = 1UL << mosi;
+    GPIO_REGS->PIN_CNF[mosi] = GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos
+                             | GPIO_PIN_CNF_INPUT_Disconnect << GPIO_PIN_CNF_INPUT_Pos
+                             | GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos
+                             | GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos
+                             | GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos;
+    // miso pin
+    GPIO_REGS->PIN_CNF[miso] = GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos
+                             | GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos
+                             | GPIO_PIN_CNF_PULL_Pulldown << GPIO_PIN_CNF_PULL_Pos
+                             | GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos
+                             | GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos;
+    // ss already configured by gpio driver
+
+    IRQn_Type irq = SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQn;
+    if(instance == 2) {
+        SPIM_REGS = reinterpret_cast<NRF_SPIM_Type *>(NRF_SPIM2_BASE);
+        irq = SPIM2_SPIS2_SPI2_IRQn;
     } else if(instance == 1) {
-        SPI_REGS = reinterpret_cast<NRF_SPI_Type *>(NRF_SPI1_BASE);
+        SPIM_REGS = reinterpret_cast<NRF_SPIM_Type *>(NRF_SPIM1_BASE);
+        irq = SPIM1_SPIS1_TWIM1_TWIS1_SPI1_TWI1_IRQn;
     } else {
-        SPI_REGS = reinterpret_cast<NRF_SPI_Type *>(NRF_SPI2_BASE);
+        SPIM_REGS = reinterpret_cast<NRF_SPIM_Type *>(NRF_SPIM0_BASE);
+        irq = SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQn;
     }
 
     this->chip_select.set();
 
-    SPI_REGS->ENABLE = 0;
-    SPI_REGS->PSEL.SCK = sck;
-    SPI_REGS->PSEL.MOSI = mosi;
-    SPI_REGS->PSEL.MISO = miso;
-    SPI_REGS->FREQUENCY = SPI_FREQUENCY_FREQUENCY_M8;
+    SPIM_REGS->ENABLE = 0;
+    SPIM_REGS->PSEL.SCK = sck;
+    SPIM_REGS->PSEL.MOSI = mosi;
+    SPIM_REGS->PSEL.MISO = miso;
+    SPIM_REGS->FREQUENCY = SPI_FREQUENCY_FREQUENCY_M8;
 
-    SPI_REGS->CONFIG = (0x03 << 1); //Sample on trailing edge of clock, shift serial data on leading edge, SCK polarity Active low
-    SPI_REGS->EVENTS_READY = 0;
-    SPI_REGS->ENABLE = (SPI_ENABLE_ENABLE_Enabled << SPI_ENABLE_ENABLE_Pos);
+    SPIM_REGS->CONFIG = (0x03 << 1); //Sample on trailing edge of clock, shift serial data on leading edge, SCK polarity Active low
+    SPIM_REGS->EVENTS_ENDRX = 0;
+    SPIM_REGS->EVENTS_ENDTX = 0;
+    SPIM_REGS->EVENTS_END = 0;
+
+    SPIM_REGS->INTENSET = (1 << 1)      // Stopped
+                        | (1 << 6)      // End
+                        | (1 << 19);    // Started
+
+    SPIM_REGS->ENABLE = (SPIM_ENABLE_ENABLE_Enabled << SPIM_ENABLE_ENABLE_Pos);
+
+    NVIC_SetPriority(irq, 2);
+    NVIC_EnableIRQ(irq);
 }
+
 Spi::~Spi()
 {
-    SPI_REGS->ENABLE = 0;
+    SPIM_REGS->ENABLE = 0;
 }
 
 void Spi::send(const uint8_t * buffer, uint32_t len)
 {
     this->chip_select.clear();
-    for(unsigned int i = 0; i < len; i++) {
-        this->transfer(buffer[i]);
-    }
+    this->xfer_active = true;
+
+    SPIM_REGS->TXD.PTR = reinterpret_cast<uint32_t>(buffer);
+    SPIM_REGS->TXD.MAXCNT = len;
+    SPIM_REGS->TXD.LIST = 0;
+
+    SPIM_REGS->RXD.PTR = 0;
+    SPIM_REGS->RXD.MAXCNT = 0;
+    SPIM_REGS->RXD.LIST = 0;
+
+    SPIM_REGS->EVENTS_END = 0;
+
+    SPIM_REGS->TASKS_START = 1;
+
+    // FIXME: LOW POWER???
+    while(this->xfer_active);
+
     this->chip_select.set();
 }
 
 void Spi::recv(uint8_t * buffer, uint32_t len)
 {
-    this->chip_select.clear();
-    for(unsigned int i = 0; i < len; i++) {
-        buffer[i] = this->transfer(buffer[i]);
-    }
-    this->chip_select.set();
+    // FIXME: not implemented yet
 }
 
-uint32_t Spi::transfer(uint32_t data)
+void Spi::handle()
 {
-    volatile uint32_t ret;
-    SPI_REGS->EVENTS_READY = 0;
-    SPI_REGS->TXD = data;
-    while(SPI_REGS->EVENTS_READY == 0) {;}
-    ret = SPI_REGS->RXD;
-    return ret;
-}
+    if((SPIM_REGS->INTENSET & (1 << 6)) && (SPIM_REGS->EVENTS_END == 1)) {
+        SPIM_REGS->EVENTS_END = 0;
+        this->xfer_active = false;
+    }
+
+    if((SPIM_REGS->INTENSET & (1 << 19)) && (SPIM_REGS->EVENTS_STARTED == 1)) {
+        SPIM_REGS->EVENTS_STARTED = 0;
+    }
+
+    if((SPIM_REGS->INTENSET & (1 << 1)) && (SPIM_REGS->EVENTS_STOPPED == 1)) {
+        SPIM_REGS->EVENTS_STOPPED = 0;
+        this->xfer_active = false;
+    }
+}

src/platform/nrf52/spi.h

@@ -4,9 +4,13 @@
 #include "gpio_interface.h"
 #include "spi_interface.h"
 
+#include "platform/nrf52/InterruptHandler.h"
+
 namespace pinetime::platform::nrf52 {
 
-class Spi : public pinetime::interfaces::SpiInterface
+class Spi
+    : public pinetime::platform::nrf52::InterruptHandler
+    , public pinetime::interfaces::SpiInterface
 {
 public:
     Spi(uint32_t instance, uint32_t sck, uint32_t mosi, uint32_t miso, pinetime::interfaces::GpioInterface & cs);
@@ -17,7 +21,10 @@ public:
 private:
     uint32_t transfer(uint32_t);
 
+    void handle() override;
+
     pinetime::interfaces::GpioInterface & chip_select;
+    volatile bool xfer_active;
 };
 
 }

src/st7789.cc

@@ -1,3 +1,4 @@
+#include <array>
 #include <cstdint>
 
 #include "st7789.h"
@@ -115,17 +116,21 @@ void St7789::send_data(uint8_t data)
 
 void St7789::clear(uint16_t Color)
 {
-    unsigned int i,j;
+    unsigned int odd = 0;
+    std::array<uint8_t, 240> line;
+    for(auto it = line.begin(); it != line.end(); ++it) {
+        if(odd % 2 == 0) {
+            *it = static_cast<uint8_t>((Color >> 8) & 0xff);
+        } else {
+            *it = static_cast<uint8_t>(Color & 0xff);
+        }
+        odd++;
+    }
 
     set_windows(0, 0, 240, 240);
     this->data_command.set();
-    for(i = 0; i < 240; i++) {
-        for(j = 0; j < 240; j++){
-            uint8_t c = (Color >> 8) & 0xff;
-            this->spi.send(&c, 1);
-            c = Color & 0xff;
-            this->spi.send(&c, 1);
-        }
+    for(unsigned int i = 0; i < 240 * 2; i++) {
+        this->spi.send(line.data(), line.size());
     }
 }
 

src/virtual_timer/VirtualTimer.cc

@@ -0,0 +1,38 @@
+#include "virtual_timer/VirtualTimerDistributor.h"
+#include "virtual_timer/VirtualTimer.h"
+
+using namespace pinetime::virtual_timer;
+
+VirtualTimer::VirtualTimer(uint64_t period_ms)
+    : period(period_ms)
+{
+}
+
+void VirtualTimer::timer_enable()
+{
+    VirtualTimerDistributor & distri = VirtualTimerDistributor::instance();
+    this->start_time = distri.tick();
+    distri.register_timer(this);
+}
+
+void VirtualTimer::timer_disable()
+{
+    VirtualTimerDistributor::instance().unregister_timer(this);
+}
+
+void VirtualTimer::timer_notification(uint64_t tick_ms)
+{
+    if((tick_ms - this->start_time) >= (this->period)) {
+        this->notification();
+    }
+}
+
+void VirtualTimer::timer_set_period_ms(uint64_t period_ms)
+{
+    this->period = period_ms;
+}
+
+// void VirtualTimer::notify()
+// {
+//     asm volatile("nop");
+// }

src/virtual_timer/VirtualTimer.h

@@ -0,0 +1,30 @@
+#ifndef __VIRTUAL_TIMER_VIRTUALTIMER_H__
+#define __VIRTUAL_TIMER_VIRTUALTIMER_H__
+
+#include "VirtualTimerInterface.h"
+
+namespace pinetime::virtual_timer
+{
+
+class VirtualTimer
+    : public pinetime::interfaces::VirtualTimerInterface
+{
+public:
+    VirtualTimer(uint64_t);
+
+    void timer_enable() override;
+    void timer_disable() override;
+    void timer_notification(uint64_t) override;
+
+    void timer_set_period_ms(uint64_t);
+
+    virtual void notification() = 0;
+
+private:
+    uint64_t period;
+    uint64_t start_time;
+};
+
+}
+
+#endif

src/virtual_timer/VirtualTimerDistributor.cc

@@ -0,0 +1,73 @@
+#include "virtual_timer/VirtualTimer.h"
+#include "virtual_timer/VirtualTimerDistributor.h"
+
+using namespace pinetime::virtual_timer;
+using namespace pinetime::interfaces;
+
+VirtualTimerDistributor::VirtualTimerDistributor(pinetime::interfaces::HwTimerInterface & timer)
+    : hw_timer(timer)
+    , num_registered_timers(0)
+{
+    for(auto it = this->virtual_timer_list.begin(); it != this->virtual_timer_list.end(); ++it) {
+        *it = nullptr;
+    }
+}
+
+void VirtualTimerDistributor::register_timer(VirtualTimerInterface *timer)
+{
+    volatile bool enable = false;
+    if(num_registered_timers == MAX_TIMERS) {
+        // FIXME: Error notification
+        return;
+    }
+    if(num_registered_timers == 0) {
+        // Timer list is empty - so - hw timer isn't running
+        enable = true;
+    } else {
+        // Check if timer already registered
+        for(auto it = this->virtual_timer_list.begin(); it != this->virtual_timer_list.end(); ++it) {
+            if(*it == timer) {
+                return;
+            }
+        }
+    }
+    for(auto it = this->virtual_timer_list.begin(); it != this->virtual_timer_list.end(); ++it) {
+        if(*it == nullptr) {
+            *it = timer;
+            num_registered_timers++;
+            break;
+        }
+    }
+    if(enable) {
+        hw_timer.enable_timer();
+    }
+}
+
+void VirtualTimerDistributor::unregister_timer(VirtualTimerInterface *timer)
+{
+    for(auto it = this->virtual_timer_list.begin(); it != this->virtual_timer_list.end(); ++it) {
+        if(*it == timer) {
+            *it = nullptr;
+            num_registered_timers--;
+            break;
+        }
+    }
+    if(num_registered_timers == 0) {
+        hw_timer.disable_timer();
+    }
+}
+
+void VirtualTimerDistributor::notify(uint64_t time_ms)
+{
+    for(auto it = this->virtual_timer_list.begin(); it != this->virtual_timer_list.end(); ++it) {
+        if(*it != nullptr) {
+            VirtualTimerInterface *vt = *it;
+            vt->timer_notification(time_ms);
+        }
+    }
+}
+
+uint64_t VirtualTimerDistributor::tick()
+{
+    return hw_timer.tick();
+}

src/virtual_timer/VirtualTimerDistributor.h

@@ -0,0 +1,41 @@
+#ifndef __VIRTUAL_TIMER_VIRTUALTIMERDISTRIBUTOR_H__
+#define __VIRTUAL_TIMER_VIRTUALTIMERDISTRIBUTOR_H__
+
+#include <array>
+
+#include "HwTimerInterface.h"
+#include "VirtualTimerInterface.h"
+
+namespace pinetime::virtual_timer
+{
+class VirtualTimerDistributor;
+}
+extern pinetime::virtual_timer::VirtualTimerDistributor virtual_timer_distributor;
+
+namespace pinetime::virtual_timer
+{
+
+class VirtualTimerDistributor
+{
+    public:
+        VirtualTimerDistributor(pinetime::interfaces::HwTimerInterface &);
+
+        static inline VirtualTimerDistributor& instance() { return virtual_timer_distributor; }
+
+        void register_timer(pinetime::interfaces::VirtualTimerInterface *);
+        void unregister_timer(pinetime::interfaces::VirtualTimerInterface *);
+
+        void notify(uint64_t);
+        uint64_t tick();
+
+    private:
+        static const uint32_t MAX_TIMERS = 8;
+
+        std::array<pinetime::interfaces::VirtualTimerInterface *, MAX_TIMERS> virtual_timer_list;
+        pinetime::interfaces::HwTimerInterface & hw_timer;
+        uint32_t num_registered_timers;
+};
+
+}
+
+#endif