1 files changed, 111 insertions, 0 deletions
diff --git a/protocol/ibm4704.h b/protocol/ibm4704.h
new file mode 100644
index 0000000000..ff8a5b7718
--- /dev/null
+++ b/protocol/ibm4704.h
@@ -0,0 +1,111 @@
+/*
+Copyright 2014 Jun WAKO <wakojun@gmail.com>
+*/
+#ifndef IBM4704_H
+#define IBM4704_H
+
+#define IBM4704_ERR_NONE        0
+#define IBM4704_ERR_STARTBIT    1
+#define IBM4704_ERR_PARITY      0x70
+
+
+void ibm4704_init(void);
+uint8_t ibm4704_send(uint8_t data);
+uint8_t ibm4704_recv_response(void);
+uint8_t ibm4704_recv(void);
+
+
+/* Check pin configuration */
+#if !(defined(IBM4704_CLOCK_PORT) && \
+      defined(IBM4704_CLOCK_PIN) && \
+      defined(IBM4704_CLOCK_DDR) && \
+      defined(IBM4704_CLOCK_BIT))
+#   error "ibm4704 clock pin configuration is required in config.h"
+#endif
+
+#if !(defined(IBM4704_DATA_PORT) && \
+      defined(IBM4704_DATA_PIN) && \
+      defined(IBM4704_DATA_DDR) && \
+      defined(IBM4704_DATA_BIT))
+#   error "ibm4704 data pin configuration is required in config.h"
+#endif
+
+
+/*--------------------------------------------------------------------
+ * static functions
+ *------------------------------------------------------------------*/
+static inline void clock_lo(void)
+{
+    IBM4704_CLOCK_PORT &= ~(1<<IBM4704_CLOCK_BIT);
+    IBM4704_CLOCK_DDR  |=  (1<<IBM4704_CLOCK_BIT);
+}
+static inline void clock_hi(void)
+{
+    /* input with pull up */
+    IBM4704_CLOCK_DDR  &= ~(1<<IBM4704_CLOCK_BIT);
+    IBM4704_CLOCK_PORT |=  (1<<IBM4704_CLOCK_BIT);
+}
+static inline bool clock_in(void)
+{
+    IBM4704_CLOCK_DDR  &= ~(1<<IBM4704_CLOCK_BIT);
+    IBM4704_CLOCK_PORT |=  (1<<IBM4704_CLOCK_BIT);
+    _delay_us(1);
+    return IBM4704_CLOCK_PIN&(1<<IBM4704_CLOCK_BIT);
+}
+static inline void data_lo(void)
+{
+    IBM4704_DATA_PORT &= ~(1<<IBM4704_DATA_BIT);
+    IBM4704_DATA_DDR  |=  (1<<IBM4704_DATA_BIT);
+}
+static inline void data_hi(void)
+{
+    /* input with pull up */
+    IBM4704_DATA_DDR  &= ~(1<<IBM4704_DATA_BIT);
+    IBM4704_DATA_PORT |=  (1<<IBM4704_DATA_BIT);
+}
+static inline bool data_in(void)
+{
+    IBM4704_DATA_DDR  &= ~(1<<IBM4704_DATA_BIT);
+    IBM4704_DATA_PORT |=  (1<<IBM4704_DATA_BIT);
+    _delay_us(1);
+    return IBM4704_DATA_PIN&(1<<IBM4704_DATA_BIT);
+}
+
+static inline uint16_t wait_clock_lo(uint16_t us)
+{
+    while (clock_in()  && us) { asm(""); _delay_us(1); us--; }
+    return us;
+}
+static inline uint16_t wait_clock_hi(uint16_t us)
+{
+    while (!clock_in() && us) { asm(""); _delay_us(1); us--; }
+    return us;
+}
+static inline uint16_t wait_data_lo(uint16_t us)
+{
+    while (data_in() && us)  { asm(""); _delay_us(1); us--; }
+    return us;
+}
+static inline uint16_t wait_data_hi(uint16_t us)
+{
+    while (!data_in() && us)  { asm(""); _delay_us(1); us--; }
+    return us;
+}
+
+/* idle state that device can send */
+static inline void idle(void)
+{
+    clock_hi();
+    data_hi();
+}
+
+/* inhibit device to send 
+ * keyboard checks Data line on start bit(Data:hi) and it stops sending if Data line is low.
+ */
+static inline void inhibit(void)
+{
+    clock_hi();
+    data_lo();
+}
+
+#endif