i2c.cs

This is a Windows CE 6.0 Board Support Package for the Gumstix Verdex platform

            try
            {
                this.DeviceIoControl(IOCTL_TRANSFER2, SerializeToByteArray(packet), null);
                result = (Int32)Marshal.PtrToStructure(pResult, typeof(Int32));
                if (result < 0)
                    BusError(result);
            }
            catch (Exception)
            {
                throw new Exception("Unable to complete I2C transaction:" + Marshal.GetLastWin32Error());
            }
            finally
            {
                Marshal.FreeHGlobal(buffer);
                Marshal.FreeHGlobal(pResult);
            }
        }

        /// <summary>
        /// Transfer eight bytes (MSB first) to the I2C bus
        /// </summary>
        /// <param name="address">Slave address</param>
        /// <param name="data">MSB transfered first</param>
        public void Write(byte address, UInt64 data)
        {
            Int32 result = 0;
            IntPtr pResult = Marshal.AllocHGlobal(Marshal.SizeOf(result));

            int rawsize = Marshal.SizeOf(data);
            IntPtr buffer = Marshal.AllocHGlobal(rawsize);
            Marshal.StructureToPtr(data, buffer, false);

            Packet packet = new Packet(address, RW.WRITE, buffer, rawsize, pResult);

            try
            {
                this.DeviceIoControl(IOCTL_TRANSFER2, SerializeToByteArray(packet), null);
                result = (Int32)Marshal.PtrToStructure(pResult, typeof(Int32));
                if (result < 0)
                    BusError(result);
            }
            catch (Exception)
            {
                throw new Exception("Unable to complete I2C transaction:" + Marshal.GetLastWin32Error());
            }
            finally
            {
                Marshal.FreeHGlobal(buffer);
                Marshal.FreeHGlobal(pResult);
            }
        }

        /// <summary>
        /// Read one byte of data from the I2C bus
        /// </summary>
        /// <param name="address">Slave address</param>
        /// <param name="data">reference to data byte</param>
        public void Read(byte address, ref byte data)

        {
            Int32 result = 0;
            IntPtr pResult = Marshal.AllocHGlobal(Marshal.SizeOf(result));

            int rawsize = Marshal.SizeOf(data);
            IntPtr buffer = Marshal.AllocHGlobal(rawsize);

            Packet packet = new Packet(address, RW.READ, buffer, rawsize, pResult);

            try
            {
                this.DeviceIoControl(IOCTL_TRANSFER2, SerializeToByteArray(packet), null);
                data = (Byte)Marshal.PtrToStructure(buffer, typeof(Byte));
                result = (Int32)Marshal.PtrToStructure(pResult, typeof(Int32));
                if (result < 0)
                    BusError(result);
            }
            catch (Exception)
            {
                throw new Exception("Unable to complete I2C transaction:" + Marshal.GetLastWin32Error());
            }
            finally
            {
                Marshal.FreeHGlobal(buffer);
                Marshal.FreeHGlobal(pResult);
            }
        }

        /// <summary>
        /// Read two bytes from the I2C bus
        /// </summary>
        /// <param name="address">Slave address</param>
        /// <param name="data">reference to data word MSB contains first read byte</param>
        public void Read(byte address, ref UInt16 data)
        {
            Int32 result = 0;
            IntPtr pResult = Marshal.AllocHGlobal(Marshal.SizeOf(result));

            int rawsize = Marshal.SizeOf(data);
            IntPtr buffer = Marshal.AllocHGlobal(rawsize);

            Packet packet = new Packet(address, RW.READ, buffer, rawsize, pResult);

            try
            {
                this.DeviceIoControl(IOCTL_TRANSFER2, SerializeToByteArray(packet), null);
                data = (UInt16)Marshal.PtrToStructure(buffer, typeof(UInt16));
                result = (Int32)Marshal.PtrToStructure(pResult, typeof(Int32));
                if (result < 0)
                    BusError(result);
            }
            catch (Exception)
            {
                throw new Exception("Unable to complete I2C transaction:" + Marshal.GetLastWin32Error());
            }
            finally
            {
                Marshal.FreeHGlobal(buffer);
                Marshal.FreeHGlobal(pResult);
            }
        }

        /// <summary>
        /// Read four bytes from the I2C bus
        /// </summary>
        /// <param name="address">Slave address</param>
        /// <param name="data">reference to data dword MSB contains first read byte</param>
        public void Read(byte address, ref UInt32 data)
        {
            Int32 result = 0;
            IntPtr pResult = Marshal.AllocHGlobal(Marshal.SizeOf(result));

            int rawsize = Marshal.SizeOf(data);
            IntPtr buffer = Marshal.AllocHGlobal(rawsize);

            Packet packet = new Packet(address, RW.READ, buffer, rawsize, pResult);

            try
            {
                this.DeviceIoControl(IOCTL_TRANSFER2, SerializeToByteArray(packet), null);
                data = (UInt32)Marshal.PtrToStructure(buffer, typeof(UInt32));
                result = (Int32)Marshal.PtrToStructure(pResult, typeof(Int32));
                if (result < 0)
                    BusError(result);
            }
            catch (Exception)
            {
                throw new Exception("Unable to complete I2C transaction:" + Marshal.GetLastWin32Error());
            }
            finally
            {
                Marshal.FreeHGlobal(buffer);
                Marshal.FreeHGlobal(pResult);
            }
        }

        /// <summary>
        /// Read eight bytes from the I2C bus
        /// </summary>
        /// <param name="address">Slave address</param>
        /// <param name="data">reference to data qword MSB contains first read byte</param>
        public void Read(byte address, ref UInt64 data)
        {
            Int32 result = 0;
            IntPtr pResult = Marshal.AllocHGlobal(Marshal.SizeOf(result));

            int rawsize = Marshal.SizeOf(data);
            IntPtr buffer = Marshal.AllocHGlobal(rawsize);

            Packet packet = new Packet(address, RW.READ, buffer, rawsize, pResult);

            try
            {
                this.DeviceIoControl(IOCTL_TRANSFER2, SerializeToByteArray(packet), null);
                data = (UInt64)Marshal.PtrToStructure(buffer, typeof(UInt64));
                result = (Int32)Marshal.PtrToStructure(pResult, typeof(Int32));
                if (result < 0)
                    BusError(result);
            }
            catch (Exception)
            {
                throw new Exception("Unable to complete I2C transaction:" + Marshal.GetLastWin32Error());
            }
            finally
            {
                Marshal.FreeHGlobal(buffer);
                Marshal.FreeHGlobal(pResult);
            }
        }

        #endregion

        #region P/Invoke helpers

        /// <summary>
        /// Byte array serializer
        /// </summary>
        /// <param name="anything"></param>
        /// <returns></returns>
        private static byte[] SerializeToByteArray(object anything)
        {
            int rawsize = Marshal.SizeOf(anything);
            IntPtr buffer = Marshal.AllocHGlobal(rawsize);
            Marshal.StructureToPtr(anything, buffer, false);
            byte[] rawdatas = new byte[rawsize];
            Marshal.Copy(buffer, rawdatas, 0, rawsize);
            Marshal.FreeHGlobal(buffer);
            return rawdatas;
        }

        /// <summary>
        /// De-serializer from byte array
        /// </summary>
        /// <param name="rawdatas"></param>
        /// <param name="anytype"></param>
        /// <returns></returns>
        private static object DeserializeFromByteArray(byte[] rawdatas, Type anytype)
        {
            int rawsize = Marshal.SizeOf(anytype);
            if (rawsize > rawdatas.Length)
                return null;
            IntPtr buffer = Marshal.AllocHGlobal(rawsize);
            Marshal.Copy(rawdatas, 0, buffer, rawsize);
            object retobj = Marshal.PtrToStructure(buffer, anytype);
            Marshal.FreeHGlobal(buffer);
            return retobj;
        }
        #endregion
    }
}