I've a log file which i append to every so often. (Thats the easy bit)

What i want to do is if its gets above a certain size then delete the old 1 st line before add the latest line to the bottom of the file.

Is there a way of doing this? i cant exactly read the whole file as i will run out memory

Dave thanks very much option b seems to the best and the most easy to implement

Adafruit was the place we got the plus 2's from because no where in the UK had enough stock and no stock of the plus 1's. We went for the Plus 2 thinking it would be a direct drop in replacement.

The funny thing is ive put my shield back on the plus 1 and its working as well as can be expected. Stick on the plus 2 the com2 and debugging is a nightmare.

Com 2 is set to 38400 initally until i set up the camera and the camera the baud rate to use is 115200. Then i close the port, change the baud rate and then re-open it. Any other comms after returns 0 bytes to read!

            byte[] outbuff = new byte[] { 0x56, 0x00, 0x32, 0x0C, 0x00, 0x0A, 0x00, 0x00, bPos1, bPos2, 0x00, 0x00, bLen1, bLen2, bdelay1, bdelay2 };            int numPackets = imagelength / 496;            if (imagelength > (numPackets * 496)) numPackets += 1;            byte[] imageData = new byte[imagelength];            for (int i = 0; i < numPackets; i++)            {                int pos = i*496;                // Ask for the next packet                outbuff[8] = (byte)(pos >> 8);                outbuff[9] = (byte)(pos & 0xFF);                serialPort.Write(outbuff, 0, outbuff.Length);                int bytesToRead = 506;

as soon as you step over the last line, thats it! no more debugging and the program has crashed!

compared to plus 1 the com port 2 is not behaving correctly. we got a serial camera attached and it does not get any data when we asked for it  or when we write a buffer it just hangs!!!  (Baud rate 115200)

cant test on another com port as its a sheild. Works fine the plus 1 and there are a few deployed at our customers

One the plus 2 it seems the debugging is terrible. you step over while bugging and nothing happens!!! its hard to explain

I wish i never brought the plus 2 now but no where stocked the plus 1. im a tight dead line and these kind of hassles is not what i need right now!

 serialPort = new SerialPort("COM2", 38400, Parity.None, 8, StopBits.One);

hi, sorry. its noting special

thanks mark but with we need more than 10 and need to get this working on the 2's as it will benefit everyone as there is an issue here. like i said it works fine the np1 and falls over on the np2.

changing the baud rate

 public bool ChangeBaudRate(Baud baudRate)        {            byte b1= 0x2A,b2= 0xF2;            switch (baudRate)            {                case Baud.B57600:                    b1 = 0x1C;                    b2 = 0x4C;                    break;                case Baud.B115200:                    b1 = 0x0D;                    b2 = 0xA6;                    break;            }            byte[] outbuff = new byte[] { 0x56, 0x00, 0x24, 0x03, 0x01, b1, b2 };            serialPort.Write(outbuff, 0, 7);            byte[] inbuff = WaitForResponse(5, 50);            if ((inbuff[0] == 0x76) && (inbuff[2] == 0x24))            {                serialPort.Close();                serialPort.BaudRate = 115200;                serialPort.Open();                return true;            }            return false;        }

i dont a small project which basically sets up the camera, takes a pic and returns the pic as a byte array and yes the same issue is there.

public byte[] GetImageData(int imagelength)        {            byte bdelay1 = 0x00;            byte bdelay2 = 0x0A;            byte bPos1 = 0x00;            byte bPos2 = 0x00;            // datalength of 496. Camera transfer maximum 512 bytes at a time. Each packet has 5 bytes at the start and 5 at the end            // and the datalength must be a multiple of 8. So 496 is the biggest we can have            byte bLen1 = 0x01;            byte bLen2 = 0xF0;            byte[] outbuff = new byte[] { 0x56, 0x00, 0x32, 0x0C, 0x00, 0x0A, 0x00, 0x00, bPos1, bPos2, 0x00, 0x00, bLen1, bLen2, bdelay1, bdelay2 };            int numPackets = imagelength / 496;            if (imagelength > (numPackets * 496)) numPackets += 1;            byte[] imageData = new byte[imagelength];            for (int i = 0; i < numPackets; i++)            {                int pos = i*496;                // Ask for the next packet                outbuff[8] = (byte)(pos >> 8);                outbuff[9] = (byte)(pos & 0xFF);                serialPort.Write(outbuff, 0, outbuff.Length);                int bytesToRead = 506;                if ((imagelength - pos) < 496)                {                    bytesToRead = (imagelength - pos) + 10;                }                WaitForData(bytesToRead, 100, imageData, pos);            }            StopPic();            return imageData;        }

as i step over the code the debug line dissapear when i do a serial.write and it looks like the system has crashed as there is nothing else i can do!

I dont think its the com port as i did a loop back test and it seemed ok but 100% sure.

got it going but ive got an issue which im not sure about yet but i tried to go back to my plus 1 and now it wont deploy to that!!!! we have devices with version 1 out there

with have the new batch and ive upgraded to 4.2.2. also updated the netdunino sdk. ive already got the 4.2 qef sdk installed but when i try to deploy my old netdunino plus code to the plus 2 it fails!!!! please help