Just a follow-up on this.
This is an actual *issue* IMHO, and the reason why I've never been able to
read beyond some address! If I modify the function so CRC bytes are actually
read when reaching end of sector, it works !
function sd_data_byte'get() return byte is
var byte x, data_byte
if sd_byte_count == 0 then -- beginning of sector read
while spi_master != 0xFE loop -- wait till data is ready to read
end loop
end if
data_byte = spi_master -- get data byte
sd_byte_count = sd_byte_count + 1 -- increment byte_count
if sd_byte_count == 512 then -- end of sector read
sd_byte_count = 0
sd_sector_count = sd_sector_count + 1 -- increment sector number
x = spi_master -- get junk crc data, crc is
disabled
x = spi_master -- get junk crc data, crc is
disabled
end if
return data_byte
end function
Matt, can you confirm there's a trouble here ?
Cheers,
Seb
2011/5/2 Sebastien Lelong <[email protected]>
> Hi Matt,
>
> BTW, I found some potential issue, or at least waste of code in sd_card.jal
> lib:
>
> Here's the guilty function:
>
> ---
> function sd_data_byte'get() return byte is
> var byte x, data_byte
>
> if sd_byte_count == 0 then -- beginning of sector read
> while spi_master != 0xFE loop -- wait till data is ready to read
> end loop
> end if
>
> data_byte = spi_master -- get data byte
>
> if sd_byte_count == 512 then -- end of sector read
> sd_sector_count = sd_sector_count + 1 -- increment sector number
> x = spi_master -- get junk crc data, crc is
> disabled
> x = spi_master -- get junk crc data, crc is
> disabled
> end if
>
> sd_byte_count = sd_byte_count + 1 -- increment byte_count
> if sd_byte_count == 512 then
> sd_byte_count = 0
> end if
>
> return data_byte
> end function
> ---
>
> When sd_byte_count = 511:
> - enter the function
> - you read data from spi
> - sd_byte_count is incremented, now is 512
> - since it's 512, it then sets to 0 (last "if")
>
> As a consequence:
>
> if sd_byte_count == 512 then -- end of sector read
> sd_sector_count = sd_sector_count + 1 -- increment sector number
> x = spi_master -- get junk crc data, crc is
> disabled
> x = spi_master -- get junk crc data, crc is
> disabled
> end if
>
>
> nerver gets executed.
>
> Am I right ?
>
> Cheers,
> Seb
>
>
> 2011/5/2 Sebastien Lelong <[email protected]>
>
>> Hi Matt,
>>
>> Thanks for your effort, but this is still the same, fat32 get stuck within
>> init procedure. I guess this is due to my fat32 partition, something is
>> wrong with it. Included is an partial hexdump of my partition, showing
>> content but only when changing. Format is:
>>
>> address b1 b2 b3 b4 b5 b6 b7 b8 b9 b0 b1 b2 b3 b4 b5 b6 |ascii ascii
>> asci|
>>
>> (b0 is b10, then b1 is b11, etc...)
>>
>> If content didn't change, you'll get "*"
>>
>> If you have time (and only if), you might be able to what's going on by
>> looking at addresses and content in order to see if data is wrong or not.
>> Careful: there may be data residues from previous experiments (but you
>> should be able to read important sectors in fat32)
>>
>> TIA
>> Cheers,
>> Seb
>>
>>
>> 2011/5/2 mattschinkel <[email protected]>
>>
>>> Seb, I finally found time to fix the FAT32_SMALL cluster size issue.
>>> Give it a try!
>>>
>>> Matt.
>>>
>>>
>
>
--
Sébastien Lelong
http://www.sirloon.net
http://sirbot.org
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