From fb71edfb6bc0702aa2ee1cc73d0822bbc37674ad Mon Sep 17 00:00:00 2001
From: fishsoupisgood <github@madingley.org>
Date: Sun, 24 Jan 2021 09:23:12 +0000
Subject: working-ish sensor

---
 humidity_sensors/app/i2c_bb.c | 157 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 157 insertions(+)
 create mode 100644 humidity_sensors/app/i2c_bb.c

(limited to 'humidity_sensors/app/i2c_bb.c')

diff --git a/humidity_sensors/app/i2c_bb.c b/humidity_sensors/app/i2c_bb.c
new file mode 100644
index 0000000..7d0d807
--- /dev/null
+++ b/humidity_sensors/app/i2c_bb.c
@@ -0,0 +1,157 @@
+#include "project.h"
+
+
+#define SCL ((u8) 1 <<4)
+#define SDA ((u8) 1 <<5)
+#define BANK GPIOB
+
+
+static u8
+set (u8 sda, u8 scl)
+{
+  u8 ret;
+
+  if (sda)
+    GPIO_WriteHigh (BANK, SDA);
+  else
+    GPIO_WriteLow (BANK, SDA);
+
+  if (scl)
+    GPIO_WriteHigh (BANK, SCL);
+  else
+    GPIO_WriteLow (BANK, SCL);
+
+  delay (4);
+  //delay_us (10);
+  ret = (GPIO_ReadInputData (BANK) & SDA) ? 1 : 0;
+
+  return ret;
+}
+
+
+
+
+u8
+i2cb_send (u8 wot)
+{
+  u8 i;
+
+  for (i = 0; i < 8; ++i) {
+    set (wot & 0x80, 0);
+    set (wot & 0x80, 1);
+    set (wot & 0x80, 0);
+    wot <<= 1;
+  }
+
+  set (1, 0);
+  i = set (1, 1);
+  set (1, 0);
+
+  return i;
+}
+
+u8
+i2cb_send_addr (u8 addr, u8 rnw)
+{
+  return i2cb_send (addr << 1 | rnw);
+}
+
+int
+i2cb_send_data (u8 d)
+{
+  return i2cb_send (d);
+}
+
+u8
+i2cb_read (u8 ack)
+{
+  u8 i, wot = 0;
+
+  for (i = 0; i < 8; ++i) {
+    wot <<= 1;
+    set (1, 0);
+    wot |= set (1, 1);
+    set (1, 0);
+  }
+
+  set (ack, 0);
+  set (ack, 1);
+  set (ack, 0);
+  return wot;
+}
+
+
+void
+i2cb_start (void)
+{
+  set (1, 1);
+  set (0, 1);
+  set (0, 0);
+}
+
+void
+i2cb_stop (void)
+{
+  set (0, 0);
+  set (0, 1);
+  set (1, 1);
+}
+
+
+int
+i2cb_start_transaction (u8 a, u8 rnw)
+{
+  i2cb_start();
+  return i2cb_send_addr (a, rnw);
+
+}
+
+
+void
+i2cb_reset (void)
+{
+  i2cb_start();
+  i2cb_stop();
+  i2cb_start();
+  i2cb_stop();
+}
+
+
+
+#if 0
+void
+i2cb_scan (void)
+{
+  u8 r;
+  u16 i;
+
+  i2cb_reset();
+
+  for (i = 0; i < 128; ++i) {
+    i2cb_start();
+    i2cb_stop();
+    i2cb_start();
+    r = i2cb_send ((i << 1) | I2C_WRITE);
+    i2cb_stop();
+
+    if (!r)
+      printf ("target found at %02x\n", i);
+
+  }
+
+  i2cb_reset();
+
+}
+#endif
+
+void
+i2cb_init (void)
+{
+  GPIO_Init (BANK, SDA, GPIO_MODE_OUT_OD_HIZ_SLOW);
+  GPIO_Init (BANK, SCL, GPIO_MODE_OUT_OD_HIZ_SLOW);
+
+  set (1, 1);
+  set (0, 1);
+  set (1, 0);
+  set (1, 1);
+}
-- 
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