Add gps, debug dongle support and pressure alt tables

GPS also pulled in serial support. The altitude tables take raw 11-bit
pressure sample numbers and convert them to standard pressure altitude
values.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 123 insertions, 0 deletions

diff --git a/ao_serial.c b/ao_serial.c
new file mode 100644
index 00000000..215a301d
--- /dev/null
+++ b/ao_serial.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright © 2009 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "ao.h"
+
+#define SERIAL_FIFO	32
+
+struct ao_fifo {
+	uint8_t	insert;
+	uint8_t	remove;
+	uint8_t	fifo[SERIAL_FIFO];
+};
+
+volatile __xdata struct ao_fifo	ao_usart1_rx_fifo;
+volatile __xdata struct ao_fifo	ao_usart1_tx_fifo;
+
+#define ao_fifo_insert(f,c) do { \
+	(f).fifo[(f).insert] = (c); \
+	(f).insert = ((f).insert + 1) & (SERIAL_FIFO-1); \
+} while(0)
+
+#define ao_fifo_remove(f,c) do {\
+	c = (f).fifo[(f).remove]; \
+	(f).remove = ((f).remove + 1) & (SERIAL_FIFO-1); \
+} while(0)
+
+#define ao_fifo_full(f)	((((f).insert + 1) & (SERIAL_FIFO-1)) == (f).remove)
+#define ao_fifo_empty(f)	((f).insert == (f).remove)
+
+void
+ao_serial_rx1_isr(void) interrupt 3
+{
+	if (!ao_fifo_full(ao_usart1_rx_fifo))
+		ao_fifo_insert(ao_usart1_rx_fifo, U1DBUF);
+	ao_wakeup(&ao_usart1_rx_fifo);
+}
+
+static __xdata uint8_t ao_serial_tx1_started;
+
+static void
+ao_serial_tx1_start(void)
+{
+	if (!ao_fifo_empty(ao_usart1_tx_fifo) &&
+	    !ao_serial_tx1_started)
+	{
+		ao_serial_tx1_started = 1;
+		ao_fifo_remove(ao_usart1_tx_fifo, U1DBUF);
+	}
+}
+
+void
+ao_serial_tx1_isr(void) interrupt 14
+{
+	UTX1IF = 0;
+	ao_serial_tx1_started = 0;
+	ao_serial_tx1_start();
+	ao_wakeup(&ao_usart1_tx_fifo);
+}
+
+uint8_t
+ao_serial_getchar(void) __critical
+{
+	uint8_t	c;
+	while (ao_fifo_empty(ao_usart1_rx_fifo))
+		ao_sleep(&ao_usart1_rx_fifo);
+	ao_fifo_remove(ao_usart1_rx_fifo, c);
+	return c;
+}
+
+void
+ao_serial_putchar(uint8_t c) __critical
+{
+	while (ao_fifo_full(ao_usart1_tx_fifo))
+		ao_sleep(&ao_usart1_tx_fifo);
+	ao_fifo_insert(ao_usart1_tx_fifo, c);
+	ao_serial_tx1_start();
+}
+
+void
+ao_serial_init(void)
+{
+	/* Set up the USART pin assignment */
+	PERCFG = (PERCFG & ~PERCFG_U1CFG_ALT_MASK) | PERCFG_U1CFG_ALT_2;
+
+	/* ee has already set the P2SEL bits */
+
+	/* Make the USART pins be controlled by the USART */
+	P1SEL |= (1 << 6) | (1 << 7);
+
+	/* UART mode with receiver enabled */
+	U1CSR = (UxCSR_MODE_UART | UxCSR_RE);
+
+	/* Pick a 4800 baud rate */
+	U1BAUD = 163;				/* 4800 */
+	U1GCR = 7 << UxGCR_BAUD_E_SHIFT;	/* 4800 */
+
+	/* Reasonable serial parameters */
+	U1UCR = (UxUCR_FLUSH |
+		 UxUCR_FLOW_DISABLE |
+		 UxUCR_D9_ODD_PARITY |
+		 UxUCR_BIT9_8_BITS |
+		 UxUCR_PARITY_DISABLE |
+		 UxUCR_SPB_1_STOP_BIT |
+		 UxUCR_STOP_HIGH |
+		 UxUCR_START_LOW);
+
+	IEN0 |= IEN0_URX1IE;
+	IEN2 |= IEN2_UTX1IE;
+}