I do not have a good answer at the moment. I mostly use SD card for logging and yes the FAT file system can be a bit slow.
How often is the display updated in your app?
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I do not have a good answer at the moment. I mostly use SD card for logging and yes the FAT file system can be a bit slow.
How often is the display updated in your app?
Dave
Always wear safety glasses while programming.
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So, is the FAT32 (SDFSHC32) much faster than FAT (SDFS3)? I didn't go for the FAT32 because it takes a lot of space in the chip.Originally Posted by mackrackit
The display changes whenever a new screen is selected and hopefully the transition should be smooth. What do you think would be the best way to read the data from the card the way I need it?
Robert
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Can not say exactly but FAT32 should be a little slower, larger sectors to read I guess.
Can you have the data on the card in CSV format instead of line by line? Be a little less reading.
Might post your code, maybe someone will see something?
Dave
Always wear safety glasses while programming.
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Good guess! I did some research in google and FAT32 is slower than FAT. I think that I found a solution to the problem I'm having, but I have to test it before I post it here.
My code is just the SDFS code, the EasyHID code, and the code to drive the TFT display all mixed together. I'm just testing everything together and so far my program is working fine.
Robert
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mackrackit,
I probably found a way to speed up the process of writing to the TFT display. If you write bytes to the SD card with values from 0 to 255, which is what I need
The program will sucessfully write 256 bytes to the txt file (a bunch of weird charactersCode:' Write to file FOR I = 0 TO 255 FAT_src[0] = I FAT_count = 1 Gosub FSfwrite Serout2 PORTC.6, 84, [ "Write ", Dec FAT_error, $d, $a] If (FAT_error != 0) Then Stop NEXT I). Now, when you try to read them back, it will always give you wrong values between the byte 210th and the byte 250th. However, by using only 7 bits in every byte (from 0 to 127) I can make my display work pretty fast. Have you seen this happen to you? Any comments?
Now, for some strange reason my SD card is only working the first time after I reprogram the 18F4550 chip. The second time that I restart the chip I get the following errors for the FSinit
I know what the FAT_error = 6 is (Init error), but the others I'm not sure what they are. Have you encounter these kind of errors before? Remember, it always works right after I reprogram the MCU. Any ideas?Code:FAT_error = 6 SDC_status = 2 SDC_response = 63
Thank you for all your help
Robert
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Not sure about the writing problem.
The errors.
Open SDFS and about 70 lines down it has the errors listed. #2 is "card not present", #63 I do not see.
But, to get around the problem I have this in my "SDINIT" routine.
Here is a snippet from my code template.Code:IF (FAT_error = 6) THEN SD_MAIN
Code:'############################################### SD_MAIN: TOGGLE PORTD.7 GOSUB SDINIT GOSUB SDFILENAME GOSUB SDOPEN_W GOSUB SD_WRITE GOSUB SDCLOSE RETURN '############################################################## SDINIT: ' FSInit initializes the card and reads all the preliminary information from it Gosub FSInit Serout2 PORTC.6, 16572, ["Init: ", Dec FAT_error, " ", Dec SDC_status, " ", Dec SDC_response, $d, $a] IF (FAT_error = 6) THEN SD_MAIN If (FAT_error != 0) Then Stop ' Display card directory Gosub FINDfirst ' Find first file on card While (FAT_error = 0) Serout2 PORTC.6,16572, [Str FAT_FileName\11, $d, $a] Gosub FINDnext ' Find next file on card Wend RETURN '################################################################
Dave
Always wear safety glasses while programming.
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mackrackit,
Thank you for your help. I will try that as soon as I get out of work. I will keep you posted.
Robert
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mackrackit,
Thank you. It worked. I wrote a loop
RobertCode:WHILE FAT_error = 6 GOSUB FSInit WEND
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