code:

#include <Wire.h> //Actually refers to TinyWireM.h

#define AM2320_ADDRESS (0xB8 >> 1)
#define AM2320_READREG 0x03

void setup() {
  Wire.begin();
}

void loop() {
  //wake up the sensor
  Wire.beginTransmission(AM2320_ADDRESS);
  delay(1); //Need to wait 800us to 3ms before sending endTransmission.
  uint8_t retVal = Wire.endTransmission();

  //retVal is 0x01, no ACK on address  

  delay(2); //No wait necessary before triggering read?

  //tell the sensor we want the current readings
  Wire.beginTransmission(AM2320_ADDRESS);
  Wire.write(AM2320_READREG); //Read sensor data
  Wire.write(0x00); //Start from the first register
  Wire.write(4); //Read all registers (2 bytes per sensor, 2 sensors)
  retVal = Wire.endTransmission();

  //retVal is usually 0x01, no ACK on address - occasionally 0x02, no ACK on data on the first iteration

  delay(10); //Need to wait at least 1.5ms before requesting data.

  retVal = Wire.requestFrom(AM2320_ADDRESS, 8);

  //retVal is again 0x01, no ACK on address

  union {
    byte buffer[8];
    struct {
      byte instruction;
      byte length;
      unsigned short humidity;
      short temp;
      unsigned short crc;
    } data;
  } sensor;

  for (uint8_t i = 0; i < 8; ++i) {
    if (retVal = Wire.available()) {
      sensor.buffer[i] = Wire.read();
      //retVal counts down from 8 as expected.
      //sensor.buffer fills with 03:00:04:00:00:00:00:00, expected 03:04:hh:hl:th:tl:ch:cl
    } else {
      break;
    }
  }

  delay(2000);
}