sam3x: Add USART registers and come convenience functions.

lib/sam3x/Makefile

@@ -28,7 +28,7 @@ CFLAGS		= -Os -g -Wall -Wextra -I../../include -fno-common \
 		  -ffunction-sections -fdata-sections -MD -DSAM3X
 # ARFLAGS	= rcsv
 ARFLAGS		= rcs
-OBJS		= gpio.o pmc.o
+OBJS		= gpio.o pmc.o usart.o
 
 VPATH += ../usb:../cm3
 

lib/sam3x/usart.c

@@ -0,0 +1,93 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2013 Gareth McMullin <gareth@blacksphere.co.nz>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libopencm3/sam3x/usart.h>
+
+void usart_set_databits(u32 usart, int bits)
+{
+	USART_MR(usart) = (USART_MR(usart) & ~USART_MR_CHRL_MASK) |
+			((bits - 5) << 6);
+}
+
+void usart_set_stopbits(u32 usart, enum usart_stopbits sb)
+{
+	USART_MR(usart) = (USART_MR(usart) & ~USART_MR_NBSTOP_MASK) |
+			(sb << 12);
+}
+
+void usart_set_parity(u32 usart, enum usart_parity par)
+{
+	USART_MR(usart) = (USART_MR(usart) & ~USART_MR_PAR_MASK) | (par << 9);
+}
+
+void usart_set_mode(u32 usart, enum usart_mode mode)
+{
+	USART_CR(usart) =
+		(mode & USART_MODE_RX) ? USART_CR_RXEN : USART_CR_RXDIS;
+	USART_CR(usart) =
+		(mode & USART_MODE_TX) ? USART_CR_TXEN : USART_CR_TXDIS;
+}
+
+void usart_set_flow_control(u32 usart, enum usart_flowcontrol fc)
+{
+	USART_MR(usart) = (USART_MR(usart) & ~USART_MR_MODE_MASK) |
+			(fc ? USART_MR_MODE_HW_HANDSHAKING : 0);
+}
+
+void usart_enable(u32 usart)
+{
+}
+
+void usart_disable(u32 usart)
+{
+}
+
+void usart_send(u32 usart, u16 data)
+{
+	USART_THR(usart) = data;
+}
+
+u16 usart_recv(u32 usart)
+{
+	return USART_RHR(usart) & 0x1f;
+}
+
+void usart_wait_send_ready(u32 usart)
+{
+	while ((USART_CSR(usart) & USART_CSR_TXRDY) == 0);
+}
+
+void usart_wait_recv_ready(u32 usart)
+{
+	while ((USART_CSR(usart) & USART_CSR_RXRDY) == 0);
+}
+
+void usart_send_blocking(u32 usart, u16 data)
+{
+	usart_wait_send_ready(usart);
+	usart_send(usart, data);
+}
+
+u16 usart_recv_blocking(u32 usart)
+{
+	usart_wait_recv_ready(usart);
+
+	return usart_recv(usart);
+}
+