Inline uart code

Makefile

 PRG            = crowbx
-OBJ            = crowbx.o midi.o dac.o uart.o gate.o poly.o mono.o list.o vibrato.o poly2.o clamp_add.o pitch.o pitch_env.o vibrato_rate.o mono2.o voice.o
+OBJ            = crowbx.o midi.o dac.o gate.o poly.o mono.o list.o vibrato.o poly2.o clamp_add.o pitch.o pitch_env.o vibrato_rate.o mono2.o voice.o
 MCU_TARGET = atmega328p
 
 OPTIMIZE       = -O3

crowbx.c

+#include <avr/interrupt.h>
 #include <avr/io.h>
+#include <util/atomic.h>
 
 #include "array_size.h"
 #include "dac.h"
@@ -10,9 +12,58 @@
 #include "pitch_env.h"
 #include "poly.h"
 #include "poly2.h"
+#include "uart.h"
 #include "vibrato.h"
 #include "voice.h"
 
+static struct {
+	uint8_t data[16];
+	uint8_t head;
+	uint8_t tail;
+} uart_buffer;
+
+void uart_buffer_push(uint8_t x) {
+	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+		uart_buffer.data[uart_buffer.tail] = x;
+		uart_buffer.tail =
+		    (uart_buffer.tail + 1) % ARRAY_SIZE(uart_buffer.data);
+	}
+}
+
+uint8_t uart_buffer_pop(uint8_t *x) {
+	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+		if (uart_buffer.head == uart_buffer.tail) {
+			return 1; // error: uart_buffer is empty
+		}
+
+		*x = uart_buffer.data[uart_buffer.head];
+		uart_buffer.head =
+		    (uart_buffer.head + 1) % ARRAY_SIZE(uart_buffer.data);
+	}
+
+	return 0;
+}
+
+ISR(USART_RX_vect) {
+	uint8_t uart_status = UCSR0A;
+	if (!(uart_status & _BV(RXC0))) {
+		// No UART data available
+		return;
+	}
+
+	// Read data to clear all status bits
+	uint8_t uart_data = UDR0;
+
+	if (uart_status & (_BV(FE0) | _BV(DOR0) | _BV(UPE0))) {
+		// There was a UART error
+		return;
+	}
+
+	uart_buffer_push(uart_data);
+}
+
+uint8_t uart_read(uint8_t *data) { return uart_buffer_pop(data); }
+
 struct {
 	void (*init)(void);
 	void (*note_on)(uint8_t n);
@@ -42,12 +93,23 @@ void io_init(void) {
 	// PORTD0 is UART RX. Set all other PORTD pins output, to save power.
 	DDRD = _BV(PORTD1) | _BV(PORTD2) | _BV(PORTD3) | _BV(PORTD4) |
 	       _BV(PORTD5) | _BV(PORTD6) | _BV(PORTD7);
-}
 
-void clock_init(void) {
 	// Run Timer0 (8-bit timer) at F_CPU/1024 -- faster incurs roll arounds.
 	// Use 16 bit timer?
 	TCCR0B |= _BV(CS00) | _BV(CS02);
+
+	// Assuming f_cpu is 16 MHz, this gives us 31250 baud
+	UBRR0H = 0;
+	UBRR0L = 31;
+
+	// Enable UART0 RX and RX interrupt
+	UCSR0B = _BV(RXEN0) | _BV(RXCIE0);
+
+	// Enable pull-up resistor on RX pin
+	PORTD |= _BV(PORTD0);
+
+	// Globally enable interrupts
+	sei();
 }
 
 void program_change(uint8_t pgm) {
@@ -104,7 +166,6 @@ int main(void) {
 	io_init();
 	dac_init();
 	midi_init();
-	clock_init();
 	pitch_init();
 	program_change(0);
 

midi-test.h

@@ -32,7 +32,6 @@ uint8_t midi_load(uint8_t *status, uint8_t *data1, uint8_t *data2);
 	}
 
 // Fake uart functions to let midi.c compile
-void uart_init(void) {}
 uint8_t uart_read(uint8_t *data) { return 0; }
 
 #endif

midi.c

@@ -66,10 +66,7 @@ void midi_parse(uint8_t b) {
 	midi.data[midi.data_received++] = b;
 }
 
-void midi_init() {
-	uart_init();
-	midi_status_init();
-}
+void midi_init() { midi_status_init(); }
 
 uint8_t midi_load(uint8_t *status, uint8_t *data1, uint8_t *data2) {
 	if (!midi_data_available()) {

uart.c

-#include "uart.h"
-#include "array_size.h"
-#include <avr/interrupt.h>
-#include <avr/io.h>
-#include <util/atomic.h>
-
-static struct {
-	uint8_t data[16];
-	uint8_t head;
-	uint8_t tail;
-} buffer;
-
-void buffer_push(uint8_t x) {
-	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
-		buffer.data[buffer.tail] = x;
-		buffer.tail = (buffer.tail + 1) % ARRAY_SIZE(buffer.data);
-	}
-}
-
-uint8_t buffer_pop(uint8_t *x) {
-	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
-		if (buffer.head == buffer.tail) {
-			return 1; // error: buffer is empty
-		}
-
-		*x = buffer.data[buffer.head];
-		buffer.head = (buffer.head + 1) % ARRAY_SIZE(buffer.data);
-	}
-
-	return 0;
-}
-
-ISR(USART_RX_vect) {
-	uint8_t uart_status = UCSR0A;
-	if (!(uart_status & _BV(RXC0))) {
-		// No UART data available
-		return;
-	}
-
-	// Read data to clear all status bits
-	uint8_t uart_data = UDR0;
-
-	if (uart_status & (_BV(FE0) | _BV(DOR0) | _BV(UPE0))) {
-		// There was a UART error
-		return;
-	}
-
-	buffer_push(uart_data);
-}
-
-void uart_init(void) {
-	// Assuming f_cpu is 16 MHz, this gives us 31250 baud
-	UBRR0H = 0;
-	UBRR0L = 31;
-
-	// Enable UART0 RX and RX interrupt
-	UCSR0B = _BV(RXEN0) | _BV(RXCIE0);
-
-	// Enable pull-up resistor on RX pin
-	PORTD |= _BV(PORTD0);
-
-	// Globally enable interrupts
-	sei();
-}
-
-uint8_t uart_read(uint8_t *data) { return buffer_pop(data); }

uart.h

@@ -4,6 +4,5 @@
 #include <stdint.h>
 
 uint8_t uart_read(uint8_t *data);
-void uart_init(void);
 
 #endif