USART bootloader, no ACK from GO command

[Gordon Madden]

Posted on July 25, 2017 at 21:03

Hello!

I have used

the

bootloader in the stm32f417 for firmware updating, and the GO command always worked.

Now my program is hanging while waiting for an ACK from the bootloader. My C# code for the host:

Sending GO command:

var go = new byte[] { 0x21 };

            var de = new byte[] { 0xDE };

            byte_read = 0;

            _serialPort.Write(go, 0, 1);

            _serialPort.Write(de, 0, 1);

            // Receive ACK byte

HANGS

-->   byte_read = _serialPort.ReadByte();

            if (byte_read == NACK)

            {

                //Console.WriteLine('NACK received for GO COMMAND start');

            }

I tried putting in delays and placing it inside a while loop to repeatedly send and then receive the ACK:

            var go = new byte[] { 0x21 };

            var de = new byte[] { 0xDE };

            byte_read = 0;

            while (byte_read != 0x79)

            {

                _serialPort.Write(go, 0, 1);

                Thread.Sleep(100);

                _serialPort.Write(de, 0, 1);

                Thread.Sleep(100);

                // Receive ACK byte

HANGS

-->      byte_read = _serialPort.ReadByte();

                Thread.Sleep(300);

                //Console.WriteLine('ACK = 0x{0} for GO command', byte_read.ToString('X'));

                //Console.WriteLine('');

                if (byte_read == NACK)

                {

                    //Console.WriteLine('NACK received for GO COMMAND start');

                    //Console.WriteLine('');

                }

            }

Why would sending the GO command cause the program to block on the ACK byte?

I have stepped through the code with Keil and Visual Studio in debug and can see the correct bytes being sent to the USART.

This is the tale end of the firmware update app and the update is completed. I can restart the board and the firmware is there.

Any suggestions?

Thanks!

[Tesla DeLorean]

Posted on July 25, 2017 at 21:43

Tried walking it through with RealTerm sending it hex bytes?

I don't think adding delays between them will help at all, I send strings of multiple bytes.

[Tesla DeLorean]

Posted on July 25, 2017 at 21:46

{ // Tx: 21 Go 0x08000000 SP=[0], PC=[4]

BYTE data[7] = { 0x21, 0xDE, 0x08, 0x00, 0x00, 0x00, 0x08 };

[Gordon Madden]

Posted on July 26, 2017 at 02:07

I will do that. I'm not familiar with the syntax above. Downloaded RealTerm. Set baud, parity, data, stop, and flow control. Looks like bytes can be sent using the Send tab, but what was your test setup for sending the bytes?

Thanks!