Openlog data logging on a SD card

[buntay]

Hello all,

I have been searching the internet, E-Bay, and this forum and cant find an answer to this problem so, can anybody help or does anybody wanna help designing new.
Heres what I have http://www.ebay.com/itm/261118702218?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 and this thing is great, I had it talking to and controlling a 20x2 in an hour over my home network. I had this http://www.4dsystems.com.au/prod.php?id=22 and played with it for a while but couldn't get anything to work....maybe got a bad one or something but that's neither here nor there since the file transfer protocol was quite confusing and I dont know if it would have worked for a network application. My searching led me to open log and got me thinking.

Here is my delema and thoughts.

I want to log data from a picaxe over a given period of time, I then would like to remotely log in and have it send the file back. Here is the problem, if I try to send to much data at one time the network module stalls out and locks up. I am sure it has something to do with how much data can be sent before it checks the status of the network again, so I want to send the file back in sections. I need to start sending X amount of data back wait send another chunk wait, so on and so on till whole file has been received. I know people have been doing data logging with open log but I cant find anything dealing with flow control. So how about designing a picaxe-open log system that can cover all the aspects of file data transmission

Ideas or help?

 

[srnet]

So how about designing a picaxe-open log system that can cover all the aspects of file data transmission
Ideas or help?

Good idea, although non-trivial.

Some ideas;

Since the download of the file would need to have a form of error detection and recovery to allow for non-continuous communication methods, such as Ethernet, you would need to implements random read\write of the files, (to store and retrieve specific blocks of data), checksums and a type of send and acknowledge.

 

[Jeremy Harris]

I've done a fair bit of work with both the Openlog uSD logger and the bigger SDLogger version that takes an SD card. Flow control when using a Picaxe software serial port to and from the SD card file system needs care, as both the Openlog and SDLogger are able to provide data faster than the Picaxe software serial port can reliably cope with at times.

I'm not familiar with the uDrive, but suspect you might have something similar going on. I suspect that if a hardware serial port is used to talk to the uDrive you may well get better results, as that doesn't seem to suffer from some of the sensitivities of the software serial ports on the Picaxe.

I may well be completely wrong here, but it's something that might be worth looking at.