feat: uart interrupt; remove: custom sysinit

include/derivative.h

@@ -3,7 +3,6 @@
 #include "MKL25Z4.h"
 
 // Define Clock Settings
-
 #define CORCLK_DEFAULT 20970000u  // Default Core clock, 20.97 Mhz
 #define BUSCLK_DEFAULT 10500000u  // Default Bus Rate clock, 10.5 Mhz, half of CORCLK
 
@@ -18,3 +17,6 @@
 
 extern uint32_t CORCLK;
 extern uint32_t BUSCLK;
+extern volatile uint32_t ms_ticks;
+extern void SysTick_Handler(void);
+extern void UART1_IRQHandler(void);

include/systick.h

@@ -6,19 +6,9 @@
 extern volatile uint32_t ms_ticks;
 
 static inline void spin(volatile uint32_t count) {
-    if (count == 0) return;
     while (count--) asm("nop");
 }
 
-static inline void systick_init(uint32_t ticks) {
-    if ((ticks - 1) > 0xffffff) return;  // Systick timer is 24 bit
-    SysTick->LOAD = ticks - 1;
-    SysTick->VAL = 0;
-    SysTick->CTRL = SysTick_CTRL_ENABLE_Msk        // Enable systick timer
-                    | SysTick_CTRL_TICKINT_Msk     // Enable interrupt
-                    | SysTick_CTRL_CLKSOURCE_Msk;  // Use butin-in clock
-}
-
 // t: expiration time, prd: period
 static inline bool timer_expired(uint32_t *t, uint32_t prd) {
     if (ms_ticks + prd < *t) *t = 0;                         // Time wrapped? Reset timer

include/uart.h

@@ -42,6 +42,11 @@ static inline void uart_init(UART_Type *UART, unsigned long baud) {
 }
 
 static inline void uart_rie_enable(UART_Type *UART) {
+    // Enable UART interrupt
+    if (UART == UART1)
+        NVIC_EnableIRQ(UART1_IRQn);
+    else if (UART == UART2)
+        NVIC_EnableIRQ(UART2_IRQn);
     UART->C2 |= UART_C2_RIE_MASK;  // Receiver interrupt enable
 }
 
@@ -77,10 +82,7 @@ static inline size_t uart_getline(UART_Type *UART, char *buf) {
         while (!uart_read_ready(UART)) asm("nop");
         *(uint8_t *)buf = (unsigned char)uart_read_byte(UART);
         cnt += 1;
-        if (*(uint8_t *)buf == 0x0d) {
+        if (*(uint8_t *)buf == 0x0a) break;
-            *(uint8_t *)buf = 0x0a;
-            break;
-        }
         (uint8_t *)buf++;
     }
     return cnt;

main.c

@@ -6,9 +6,9 @@
 
 int main(void) {
     // Initialize
-    systick_init(CORCLK / 1000);  // Period of systick timer : 1ms
+    SysTick_Config(CORCLK / 1000);  // Period of systick timer : 1ms
-    uart_init(UART_MSG, 9600);    // Initialize UART1 with PC
+    uart_init(UART_MSG, 9600);      // Initialize UART1 with PC
-    uart_rie_enable(UART_MSG);    // Enable UART1 receive interrupt
+    uart_rie_enable(UART_MSG);      // Enable UART1 receive interrupt
 
     uart_printf(UART_MSG, "System Clock: %lu\r\n", CORCLK);
     uart_printf(UART_MSG, "Bus Clock: %lu\r\n", BUSCLK);
@@ -16,7 +16,7 @@ int main(void) {
     uint32_t timer = 0;
     for (;;) {
         if (timer_expired(&timer, 1000)) {
-            uart_printf(UART_MSG, "LED: %d, tick: %lu\r\n", GPIOC->PDOR & BIT(12) ? 1 : 0, ms_ticks);
+            uart_printf(UART_MSG, "UART RD: %d, tick: %lu\r\n", UART_MSG->S1 & UART_S1_RDRF_MASK ? 1 : 0, ms_ticks);
         }
     }
 }

src/derivative.c

@@ -1,4 +1,5 @@
 #include "derivative.h"
+#include "uart.h"
 
 uint32_t CORCLK = CORCLK_DEFAULT;
 uint32_t BUSCLK = BUSCLK_DEFAULT;
@@ -7,3 +8,13 @@ uint32_t BUSCLK = BUSCLK_DEFAULT;
 volatile uint32_t ms_ticks;
 
 void SysTick_Handler(void) { ms_ticks++; }
+
+void UART1_IRQHandler(void) {
+    if (UART1->S1 & UART_S1_RDRF_MASK) {
+        char buf[64];
+        size_t len = uart_getline(UART1, buf);
+        uart_printf(UART_MSG, "%d: ", len);
+        uart_write_buf(UART_MSG, buf, len);
+        buf[0] = UART1->D;
+    }
+}

src/startup.c

@@ -21,8 +21,8 @@ static void copy_data(void) {
     memcpy(_sdata, _sidata, (size_t)(_edata - _sdata));
 }
 
-uint32_t MCGOUTClock;
+static uint32_t MCGOUTClock;
-uint16_t Divider;
+static uint16_t Divider;
 
 static void FLL_clock(void) {
     /*
@@ -173,14 +173,6 @@ __attribute__((naked, noreturn)) void _reset(void) {
 // Interrupt service routine (ISR)
 extern void _estack(void);  // Defined in link.ld
 
-/*
-    Set tab (the vector table) in the section ".vectors"
-    and the size of the vector table is 16 + 32
-    the first 16 * 4 bytes are reserved for the Cortex-M0+ core
-    the first one is the initial stack pointer
-    the second one is the initial program counter
-*/
-
 void Default_Handler() { __asm("bkpt"); }
 void NMI_Handler() __attribute__((weak, alias("Default_Handler")));
 void HardFault_Handler() __attribute__((weak, alias("Default_Handler")));
@@ -188,6 +180,7 @@ void SVC_Handler() __attribute__((weak, alias("Default_Handler")));
 void PendSV_Handler() __attribute__((weak, alias("Default_Handler")));
 void SysTick_Handler() __attribute__((weak, alias("Default_Handler")));
 
+// Interrupt request (IRQ) Handlers
 void DMA0_IRQHandler() __attribute__((weak, alias("Default_Handler")));
 void DMA1_IRQHandler() __attribute__((weak, alias("Default_Handler")));
 void DMA2_IRQHandler() __attribute__((weak, alias("Default_Handler")));