From 26d04ee4de6c0306120c5ee1616c3e51f51328f6 Mon Sep 17 00:00:00 2001
From: Sadeep Madurange <sadeep@asciimx.com>
Date: Mon, 4 Aug 2025 21:17:51 +0800
Subject: Refactor UART code to separate file.

---
 Makefile |  2 +-
 fpm.c    | 17 ++++++-----------
 main.c   | 16 ++++------------
 uart.c   | 31 +++++++++++++++++++++++++++++++
 uart.h   | 10 ++++++++++
 5 files changed, 52 insertions(+), 24 deletions(-)
 create mode 100644 uart.c
 create mode 100644 uart.h

diff --git a/Makefile b/Makefile
index 8f22e14..ee25780 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@ MCU = atmega328p
 PORT = /dev/cuaU0
 TARGET = app
 
-SRC = main.c fpm.c 
+SRC = main.c uart.c fpm.c
 OBJ = $(SRC:.c=.o)
 
 CFLAGS = -std=gnu99
diff --git a/fpm.c b/fpm.c
index 6599996..e85ee94 100644
--- a/fpm.c
+++ b/fpm.c
@@ -1,8 +1,7 @@
-#include <avr/io.h>
 #include <util/delay.h>
-#include <util/setbaud.h>
 
 #include "fpm.h"
+#include "uart.h"
 
 #define MAXPDLEN                   64
 
@@ -15,16 +14,12 @@
 
 static inline uint8_t read(void)
 {
-	while (!(UCSR0A & (1 << RXC0)))
-		;
-	return UDR0;
+	return uart_recv();
 }
 
 static inline void write(uint8_t c)
 {
-	while (!(UCSR0A & (1 << UDRE0)))
-		;
-	UDR0 = c;
+	uart_send(c);
 }
 
 static inline void send(uint8_t *data, uint8_t n)
@@ -167,13 +162,13 @@ static inline uint8_t img2tz(uint8_t bufid)
 
 uint8_t fpm_init(void)
 {
-	uint8_t rc;
+	uint8_t rc, wt = 100;
 	uint16_t dt = 0;
 
 	do {
 		rc = check_pwd();
-		_delay_ms(100);
-		dt += 100;
+		dt += wt;
+		_delay_ms(wt);
 	} while (rc == 0 && dt < 500);
 
 	return rc;
diff --git a/main.c b/main.c
index 3af81c5..9c43e20 100644
--- a/main.c
+++ b/main.c
@@ -5,6 +5,7 @@
 #include <util/delay.h>
 
 #include "fpm.h"
+#include "uart.h"
 
 #define SERVO_PIN          PB1
 #define SERVO_DDR          DDRB
@@ -95,21 +96,12 @@ int main(void)
 	WDTCSR |= (1 << WDCE) | (1 << WDE);
 	WDTCSR = 0x00;
 
-	/* power on peripherals */
+	uart_init();
+
+	/* power on the FPM and the servo */
 	PWR_DDR |= (1 << PWR_FPM) | (1 << PWR_SERVO);
 	pwr_fpm_servo_on();
 
-	/* UART for FPM */
-	UBRR0H = UBRRH_VALUE;
-	UBRR0L = UBRRL_VALUE;
-#if USE_2X
-	UCSR0A |= (1 << U2X0);
-#else
-	UCSR0A &= ~(1 << U2X0);
-#endif
-	UCSR0B = (1 << TXEN0) | (1 << RXEN0);
-	UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);
-
 	/* servo */
 	TCCR1A |= (1 << WGM11);
 	TCCR1B |= (1 << WGM12) | (1 << WGM13);
diff --git a/uart.c b/uart.c
new file mode 100644
index 0000000..1a9956d
--- /dev/null
+++ b/uart.c
@@ -0,0 +1,31 @@
+#include <avr/io.h>
+#include <util/setbaud.h>
+
+#include "uart.h"
+
+void uart_init(void)
+{
+	UBRR0H = UBRRH_VALUE;
+	UBRR0L = UBRRL_VALUE;
+#if USE_2X
+	UCSR0A |= (1 << U2X0);
+#else
+	UCSR0A &= ~(1 << U2X0);
+#endif
+	UCSR0B = (1 << TXEN0) | (1 << RXEN0);
+	UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);
+}
+
+uint8_t uart_recv(void)
+{
+	while (!(UCSR0A & (1 << RXC0)))
+		;
+	return UDR0;
+}
+
+void uart_send(uint8_t c)
+{
+	while (!(UCSR0A & (1 << UDRE0)))
+		;
+	UDR0 = c;
+}
diff --git a/uart.h b/uart.h
new file mode 100644
index 0000000..c5fc87e
--- /dev/null
+++ b/uart.h
@@ -0,0 +1,10 @@
+#ifndef UART_H
+#define UART_H
+
+void uart_init(void);
+
+uint8_t uart_recv(void);
+
+void uart_send(uint8_t c);
+
+#endif /* UART_H */
-- 
cgit v1.2.3