Help with writing to SD file please!

Hugh

Hi folks,

I'm scratching my head and going round in circles - I'll soon be dizzy and bald, so any assistance you could suggest would be gratefully received by me!

I have some data in a variable of up to 40 bytes in length. I can display the contents of the last fifteen bytes (the portion of interest) to an LCD display easily, but I don't seem to be able to write it to a file on an SD card using FSRW v2.4.

The code looks like:

r:=  sdfat.mount(0)
  sdfat.popen(string("Data5.txt"), "a") 
  repeat 11
    lcd.dec(dataIn[noparse][[/noparse]ct - charCtr])                               ' ct = length, so say = 30
    lcd.putc(32)                                                      ' charCtr starts at 15
    sdfat.pputs(num.dec(dataIn[noparse][[/noparse]ct - charCtr--]))
    sdfat.pputs(44)

What actually gets written is ".|.|.|.|.|.|.|.|.|.|.|,"

I have tried without the 'num.dec' (Num = simpleNumbers.spin), using bytemove and pwrite, and many others combinations...

It is probably staring me in the face but what am I doing wrong, or not doing?

Thanks

Bald dizzy Hugh

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Hugh - the thinking woman's Geoffrey Pyke.

Hugh

Yes, I've tried sdfat.pputc!

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Hugh - the thinking woman's Geoffrey Pyke.

lonesock

Here are a couple of things to try:
- use the same output from num.dec in the LCD and SD code
- make sure to close the file when you are done writing...if you power off or unplug the SD card, the FAT table may not be updated.
- using "pputs(44)" writes a string where the starting pointer address is 44....probably not what you want!
- verify your pins connecting to the sd card, and check the return value of the mount call.

check out the following code (I made some guesses about variables and OBJ types):

OBJ
  sdfat:        "fsrw"
  lcd:          "Serial_LCD"
  num:          "Simple_Numbers"

CON
  ct = 30
  
VAR
  long dataIn[noparse][[/noparse] 100 ]

PUB test_code | r, strptr, charCtr 
  r:=  sdfat.mount(0)
  sdfat.popen(string("Data5.txt"), "a")
  charCtr := ct 
  repeat 11
    strptr := num.dec(dataIn[noparse][[/noparse]ct - charCtr--])           ' ct = length, so say = 30   
    lcd.str( strptr )                               
    lcd.putc( " " )                                     ' charCtr starts at 15
    sdfat.pputs( strptr )
    sdfat.pputc( "," )
  sdfat.pclose

Please let me know if that changes anything.

Jonathan

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
lonesock
Piranha are people too.

Post Edited (lonesock) : 10/28/2009 9:10:44 PM GMT

Hugh

Will do – thanks!

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Hugh - the thinking woman's Geoffrey Pyke.

Mike Green

For sure, the "sdfat.pputs(44)" has to be "sdfat.pputc(44)" because "pputs" expects the address of a string (byte array).

What shows up on the LCD?

Don't forget that you have to close the file after you finish writing or the last 512 byte block won't be written to the SD card.

Hugh

Thanks chaps.

Lonesock's code as above results in a series of what I would call 'high ASCII' characters being displayed on the LCD - if I display them using...

lcd.dec(dataIn[noparse][[/noparse]ct - charCtr--])          

...they display correctly. Sometimes "data6.txt" is an empty file.

A different procedure in the same code writes various data to a file on the SD card without a problem.



▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Hugh - the thinking woman's Geoffrey Pyke.

lonesock

Hugh said...
Thanks chaps.

Lonesock's code as above results in a series of what I would call 'high ASCII' characters being displayed on the LCD - if I display them using...

lcd.dec(dataIn[noparse][[/noparse]ct - charCtr--])           

...they display correctly. Sometimes "data6.txt" is an empty file.

A different procedure in the same code writes various data to a file on the SD card without a problem.

Hmm, if displaying the same string on the LCD doesn't work, maybe something is wrong in the num.dec function? Can you connect up a TV or VGA or serial port to debug exactly what the string is that is returned by num.dec? (As an aside, in the code snippets we were using "Data5.txt", so the file "data6.txt" being empty isn't too surprising

Jonathan

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
lonesock
Piranha are people too.