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android – setting parity with controlTransfer method

Posted by: admin June 15, 2020 Leave a comment

Questions:

Anybody knows how to set the parity with the controlTransfer in Android?

I can’t find the explanation of this method’s parameters anywhere – just some generic info in the ref.

One example I found says:

conn.controlTransfer(0x40, 0x04, 0x0008, 0, null, 0, 0);    //data bit 8, parity none, stop bit 1, tx off

But I need to change the parity. Anybody has an idea?

Many thanks!

How to&Answers:

You can define the combination of bits to create your own configuration (parity, stop bit & data bit).

conn.controlTransfer(0x40, 0x04, 0x0008, 0, null, 0, 0); 

1st parameter – 0x40  – request to set or get control data

 #define FTDI_SIO_SET_DATA_REQUEST_TYPE  0x40

2nd parameter – 0x04 – type of data to be set or get

#define FTDI_SIO_RESET      0 /* Reset the port */
#define FTDI_SIO_MODEM_CTRL     1 /* Set the modem control register */
#define FTDI_SIO_SET_FLOW_CTRL  2 /* Set flow control register */
#define FTDI_SIO_SET_BAUD_RATE  3 /* Set baud rate */
#define FTDI_SIO_SET_DATA   4 /* Set the data characteristics of the port */
#define FTDI_SIO_GET_MODEM_STATUS   5 /* Retrieve current value of modern status register */
#define FTDI_SIO_SET_EVENT_CHAR 6 /* Set the event character */
#define FTDI_SIO_SET_ERROR_CHAR 7 /* Set the error character */

Third parameter – 0x0008 – data bit 8, parity none, stop bit 1, tx off – Is the actual data to be passed.

The third parameter is a 16 bit data which can be formed from the constants defined below:

Bits 0 to 7   -- Number of data bits

Bits 8 to 10  -- Parity
          0 = None
          1 = Odd
          2 = Even
          3 = Mark
          4 = Space
Bits 11 to 13 -- Stop Bits
          0 = 1
          1 = 1.5
          2 = 2
Bit 14
          1 = TX ON (break)
          0 = TX OFF (normal state)
Bit15 -- Reserved


 #define FTDI_SIO_SET_DATA_REQUEST       FTDI_SIO_SET_DATA

 #define FTDI_SIO_SET_DATA_PARITY_NONE   (0x0 << 8)
 #define FTDI_SIO_SET_DATA_PARITY_ODD    (0x1 << 8)
 #define FTDI_SIO_SET_DATA_PARITY_EVEN   (0x2 << 8)
 #define FTDI_SIO_SET_DATA_PARITY_MARK   (0x3 << 8)
 #define FTDI_SIO_SET_DATA_PARITY_SPACE  (0x4 << 8)
 #define FTDI_SIO_SET_DATA_STOP_BITS_1   (0x0 << 11)
 #define FTDI_SIO_SET_DATA_STOP_BITS_15  (0x1 << 11)
 #define FTDI_SIO_SET_DATA_STOP_BITS_2   (0x2 << 11)
 #define FTDI_SIO_SET_BREAK              (0x1 << 14)

For baud rate :

* Value Baud Rate speed
* 0×2710 300
* 0×1388 600
* 0x09C4 1200
* 0x04E2 2400
* 0×0271 4800
* 0×4138 9600
* 0x80D0 14400
* 0x809C 19200
* 0xC04E 38400
* 0×0034 57600
* 0x001A 115200
* 0x000D 230400
* 0×4006 460800
* 0×8003 921600
*/

Please refer the below links for more details:

http://read.pudn.com/downloads181/sourcecode/embed/842049/usb/serial/ftdi_sio.h__.htm

http://www.mev.co.uk/pages/Support/USB-Baud-Spoof.html