From b8094de129de17280f58d1042e6dcdd48f9eaef3 Mon Sep 17 00:00:00 2001
From: Kevin O'Connor <kevin@koconnor.net>
Date: Mon, 5 Jun 2017 12:30:49 -0400
Subject: avr: Support using serial instead of usb on AT90USB1286

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
---
 src/avr/serial.c | 42 +++++++++++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 15 deletions(-)

(limited to 'src/avr/serial.c')

diff --git a/src/avr/serial.c b/src/avr/serial.c
index 3aff121f..3221b6f0 100644
--- a/src/avr/serial.c
+++ b/src/avr/serial.c
@@ -25,29 +25,41 @@ static uint8_t transmit_pos, transmit_max;
 
 DECL_CONSTANT(SERIAL_BAUD, CONFIG_SERIAL_BAUD);
 
+// Define serial port registers on AT90USB1286
+#if !defined(UCSR0A) && defined(UCSR1A)
+#define UCSR0A UCSR1A
+#define UCSR0B UCSR1B
+#define UCSR0C UCSR1C
+#define UBRR0 UBRR1
+#define UDR0 UDR1
+#define UCSZ01 UCSZ11
+#define UCSZ00 UCSZ10
+#define U2X0 U2X1
+#define RXEN0 RXEN1
+#define TXEN0 TXEN1
+#define RXCIE0 RXCIE1
+#define UDRIE0 UDRIE1
+#define USART0_RX_vect USART1_RX_vect
+#define USART0_UDRE_vect USART1_UDRE_vect
+#endif
+
+// Define serial port registers on atmega168 / atmega328
+#if defined(USART_RX_vect)
+#define USART0_RX_vect USART_RX_vect
+#define USART0_UDRE_vect USART_UDRE_vect
+#endif
+
 void
 serial_init(void)
 {
-    if (CONFIG_SERIAL_BAUD_U2X) {
-        UCSR0A = 1<<U2X0;
-        UBRR0 = DIV_ROUND_CLOSEST(
-            CONFIG_CLOCK_FREQ, 8UL * CONFIG_SERIAL_BAUD) - 1UL;
-    } else {
-        UCSR0A = 0;
-        UBRR0 = DIV_ROUND_CLOSEST(
-            CONFIG_CLOCK_FREQ, 16UL * CONFIG_SERIAL_BAUD) - 1UL;
-    }
-
+    UCSR0A = CONFIG_SERIAL_BAUD_U2X ? (1<<U2X0) : 0;
+    uint32_t cm = CONFIG_SERIAL_BAUD_U2X ? 8 : 16;
+    UBRR0 = DIV_ROUND_CLOSEST(CONFIG_CLOCK_FREQ, cm * CONFIG_SERIAL_BAUD) - 1UL;
     UCSR0C = (1<<UCSZ01) | (1<<UCSZ00);
     UCSR0B = (1<<RXEN0) | (1<<TXEN0) | (1<<RXCIE0) | (1<<UDRIE0);
 }
 DECL_INIT(serial_init);
 
-#ifdef USART_RX_vect
-#define USART0_RX_vect USART_RX_vect
-#define USART0_UDRE_vect USART_UDRE_vect
-#endif
-
 // Rx interrupt - data available to be read.
 ISR(USART0_RX_vect)
 {
-- 
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