From 39687aa7c7b138d2a1ce2551f2400bade3b1a6fb Mon Sep 17 00:00:00 2001
From: James McKenzie <git@madingley.org>
Date: Sun, 2 Aug 2015 23:30:06 +0100
Subject: fis

---
 app/i2c.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 app/i2c.c

(limited to 'app/i2c.c')

diff --git a/app/i2c.c b/app/i2c.c
new file mode 100644
index 0000000..89249d0
--- /dev/null
+++ b/app/i2c.c
@@ -0,0 +1,132 @@
+#include "project.h"
+
+
+#define GPIO_SCL GPIOB
+#define GPIO_SDA GPIOB
+#define SCL 	GPIO13
+#define SDA	GPIO14
+
+#define I2C_BB_DELAY do { delay_us(1); } while (0)
+
+int
+i2c_bb (int scl, int sda)
+{
+  if (scl)
+    gpio_set (GPIO_SCL, SCL);
+  else
+    gpio_clear (GPIO_SCL, SCL);
+  if (sda)
+    gpio_set (GPIO_SDA, SDA);
+  else
+    gpio_clear (GPIO_SDA, SDA);
+
+  return ! !(gpio_get (GPIO_SDA, SDA) & SDA);
+
+}
+
+
+void
+i2c_bb_start (void)
+{
+  i2c_bb (1, 1);
+  I2C_BB_DELAY;
+  i2c_bb (1, 0);
+  I2C_BB_DELAY;
+  i2c_bb (0, 0);
+  I2C_BB_DELAY;
+}
+
+
+void
+i2c_bb_stop (void)
+{
+  i2c_bb (0, 0);
+  I2C_BB_DELAY;
+  i2c_bb (1, 0);
+  I2C_BB_DELAY;
+  i2c_bb (1, 1);
+  I2C_BB_DELAY;
+}
+
+int
+i2c_bb_send_data (uint8_t v)
+{
+  int c;
+
+
+  for (c = 0x80; c; c >>= 1)
+    {
+      i2c_bb (0, c & v);
+      I2C_BB_DELAY;
+      i2c_bb (1, c & v);
+      I2C_BB_DELAY;
+      i2c_bb (0, c & v);
+      I2C_BB_DELAY;
+    }
+
+  i2c_bb (0, 1);
+  I2C_BB_DELAY;
+  i2c_bb (1, 1);
+  I2C_BB_DELAY;
+  c = i2c_bb (1, 1);
+  i2c_bb (0, 1);
+
+  return c;
+}
+
+
+int
+i2c_bb_start_transaction (uint8_t a, int wnr)
+{
+  int ret;
+
+  i2c_bb_start ();
+  ret = i2c_bb_send_data (a << 1 | ! !(wnr));
+
+
+  return ret;
+}
+
+#if 0
+void
+i2c_bb_scan (void)
+{
+  int i, r;
+
+  return;
+  i2cp_reset ();
+
+  printf ("Probing bus\r\n");
+  for (i = 0; i < 128; ++i)
+    {
+      while (i2cp_lock ());
+      i2cp_start ();
+      i2cp_abort_start ();
+      i2cp_stop ();
+      i2cp_abort_stop ();
+      r = i2cp_start_transaction (i, I2C_WRITE);
+      i2cp_stop ();
+      i2cp_unlock ();
+      if (!r)
+        printf ("Found device at address 0x%x\r\n", i);
+      usart1_drain ();
+    }
+  printf ("Done\r\n");
+  i2cp_reset ();
+
+}
+#endif
+
+void
+i2c_bb_init (void)
+{
+  gpio_set_mode (GPIO_SCL, GPIO_MODE_OUTPUT_50_MHZ,
+                 GPIO_CNF_OUTPUT_OPENDRAIN, SCL);
+  gpio_set_mode (GPIO_SDA, GPIO_MODE_OUTPUT_50_MHZ,
+                 GPIO_CNF_OUTPUT_OPENDRAIN, SDA);
+
+  i2c_bb_start ();
+  i2c_bb_stop ();
+
+
+}
-- 
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