1 files changed, 114 insertions, 0 deletions

diff --git a/protocol/serial_soft.c b/protocol/serial_soft.c
new file mode 100644
index 000000000..b7d06b644
--- /dev/null
+++ b/protocol/serial_soft.c
@@ -0,0 +1,114 @@
+/*
+Copyright 2012 Jun WAKO <wakojun@gmail.com>
+
+This software is licensed with a Modified BSD License.
+All of this is supposed to be Free Software, Open Source, DFSG-free,
+GPL-compatible, and OK to use in both free and proprietary applications.
+Additions and corrections to this file are welcome.
+
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in
+  the documentation and/or other materials provided with the
+  distribution.
+
+* Neither the name of the copyright holders nor the names of
+  contributors may be used to endorse or promote products derived
+  from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include <stdbool.h>
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <util/delay.h>
+#include "serial.h"
+
+/*
+ *  Stupid Inefficient Busy-wait Software Serial
+ *  is still useful for negative logic signal like Sun protocol not supported by hardware USART.
+ */
+
+#define WAIT_US     (1000000/SERIAL_BAUD)
+
+void serial_init(void)
+{
+    SERIAL_RXD_INIT();
+}
+
+// RX ring buffer
+#define RBUF_SIZE   8
+static uint8_t rbuf[RBUF_SIZE];
+static uint8_t rbuf_head = 0;
+static uint8_t rbuf_tail = 0;
+
+uint8_t serial_recv(void)
+{
+    uint8_t data = 0;
+    if (rbuf_head == rbuf_tail) {
+        return 0;
+    }
+
+    data = rbuf[rbuf_tail];
+    rbuf_tail = (rbuf_tail + 1) % RBUF_SIZE;
+    return data;
+}
+
+//ISR(INT2_vect)
+ISR(SERIAL_RXD_VECT)
+{
+    SERIAL_RXD_INT_ENTER()
+
+    uint8_t data = 0;
+#ifdef SERIAL_BIT_ORDER_MSB
+    uint8_t pos = 0x80;
+#else
+    uint8_t pos = 0x01;
+#endif
+    // to center of start bit
+    _delay_us(WAIT_US/2);
+    do {
+        // to center of next bit
+        _delay_us(WAIT_US);
+
+        if (SERIAL_RXD_PIN&(1<<SERIAL_RXD_BIT)) {
+            data |= pos;
+        }
+#ifdef SERIAL_BIT_ORDER_MSB
+        pos >>= 1;
+#else
+        pos <<= 1;
+#endif
+    } while (pos);
+    // to center of stop bit
+    _delay_us(WAIT_US);
+
+#ifdef SERIAL_NEGATIVE_LOGIC
+    data = ~data;
+#endif
+
+    uint8_t next = (rbuf_head + 1) % RBUF_SIZE;
+    if (next != rbuf_tail) {
+        rbuf[rbuf_head] = data;
+        rbuf_head = next;
+    }
+
+    SERIAL_RXD_INT_EXIT();
+}