Init commit with many years of arduino sketches and projects. I dont know if the esp8266 includes much, but there are also libraries. I hope they dont have crazy automatic versioning through the Arduino IDE.

libraries/NewliquidCrystal/thirdparty libraries/SoftI2CMaster/examples/BMA020Soft/BMA020Soft.ino

@@ -0,0 +1,98 @@
+// Simple sketch to read out BMA020 using SoftI2C
+
+// Readout BMA020 chip
+
+// use low processor speed (you have to change the baud rate to 2400!) 
+// #define I2C_CPUFREQ (F_CPU/8)
+#define NO_INTERRUPT 1
+#define I2C_TIMEOUT 1000
+
+#define SDA_PORT PORTD
+#define SDA_PIN 3
+#define SCL_PORT PORTD
+#define SCL_PIN 5
+#include <SoftI2CMaster.h>
+#include <avr/io.h>
+
+
+#define BMAADDR 0x70
+
+int xval, yval, zval;
+
+void CPUSlowDown(void) {
+  // slow down processor by a factor of 8
+  CLKPR = _BV(CLKPCE);
+  CLKPR = _BV(CLKPS1) | _BV(CLKPS0);
+}
+  
+
+boolean setControlBits(uint8_t cntr)
+{
+  Serial.println(F("Soft reset"));
+  if (!i2c_start(BMAADDR | I2C_WRITE)) {
+    return false;
+  }
+  if (!i2c_write(0x0A)) {
+    return false;
+  }
+  if (!i2c_write(cntr)) {
+    return false;
+  }
+  i2c_stop();
+  return true;
+}
+
+boolean initBma(void)
+{
+  if (!setControlBits(B00000010)) return false;;
+  delay(100);
+  return true;
+}
+
+int readOneVal(boolean last)
+{
+  uint8_t msb, lsb;
+  lsb = i2c_read(false);
+  msb = i2c_read(last);
+  if (last) i2c_stop();
+  return (int)((msb<<8)|lsb)/64;
+}
+
+boolean readBma(void)
+{
+  xval = 0xFFFF;
+  yval = 0xFFFF;
+  zval = 0xFFFF;
+  if (!i2c_start(BMAADDR | I2C_WRITE)) return false;
+  if (!i2c_write(0x02)) return false;
+  if (!i2c_rep_start(BMAADDR | I2C_READ)) return false;
+  xval = readOneVal(false);
+  yval = readOneVal(false);
+  zval = readOneVal(true);
+  return true;
+}
+
+
+
+//------------------------------------------------------------------------------
+void setup(void) {
+#if I2C_CPUFREQ == (F_CPU/8)
+  CPUSlowDown();
+#endif
+  Serial.begin(19200); // in case of CPU slow down, change to baud rate / 8!
+  if (!initBma()) {
+    Serial.println(F("INIT ERROR"));
+  }
+
+}
+
+void loop(void){
+  if (!readBma()) Serial.println(F("READ ERROR"));
+  Serial.print(F("X="));
+  Serial.print(xval);
+  Serial.print(F("  Y="));
+  Serial.print(yval);
+  Serial.print(F("  Z="));
+  Serial.println(zval);
+  delay(300);
+}