Lpc2000

Peter,

been away for a week, but now busy again :)
Your code looks good only I'm not that familiar with Forth.
Can you shortly explane what happens when you do a r.. or w.. ? I
understand that this are the read and write commands, but is it a
function ore something or does it just writes or reads bytes from the
SPDR (data register)?

thanks,

Wouter


--- In lpc2000@yahoogroups.com, "Peter Jakacki" <peterjak@t...> wrote:
>
> I've had a few queries in regards to SD card initialization in SPI
> mode. For anyone who is interested I have included a dump of the SPI
> activity during an init. There are two examples, the first with a
> SANDISK 512M Ultra, and the second with a generic 128M SD.
> 
> The SD & FAT code are written in a Forth that I have written for the
> LPC2000s. Since this is not everyones cup of tea, I have included a
> simple dump of the activity of the SD interface. Comments are as
> normal and bytes that are read are prefixed with "r", those that are
> writes are prefixed with "w". All bytes are in hex.
> 
> Although it is possible to issue a CMD1 following a CMD0, the SANDISK
> SD CARD product manual states that ACMD41 should be used. This avoids
> confusion with MMC cards but read what SANDISK have to say in section
> 5.8. Apparently ACMD1 is an illegal command for the thin cards in SPI
> mode.
> 
> The dummy read at the start of the CMD is just to make sure that the
> SD interface is synchronized etc. This is easier than putting dummy
> reads at the end of transfers .
> 
> One thing that didn't show-up on the 128M cards but did on the 512M
> was when I was accessing high memory around 300MBs up. I would find
> that the data token response on a read block request was taking a lot
> longer. I had to either introduce a delay of 1ms in each loop or
> increase the retry counter from 8 to 4000!!! (I am running at 16Mhz
> SPI rate).
> 
> Hope this is useful.
> 
> *Peter*
> 
> ;*************************** SD CARD INITIALIZATION
> ************************
> 
> 
> ; *** Initialize a Sandisk 512M SD CARD ***
> 
> VDD OFF
> CS ON
> 5ms
> VDD ON
> 1ms
> 
> ; Dummy clocks
> CS ON
> rFF rFF rFF rFF rFF rFF rFF rFF rFF rFF
> CS OFF
> wFF wFF
> 
> ; CS is asserted to ensure that all interfaces lines are at VSS (no
> power whatsoever)
> CS ON
> rFF rFF
> CS OFF
> 5ms
> 
> ; CMD0
> CS ON
> rFF w40 w00 w00 w00 w00 w95 rFF r01
> 
> ; ACMD41 until response = 0
> CS ON
> rFF w77 w00 w00 w00 w00 w95 rFF r01
> CS ON
> rFF w69 w00 w00 w00 w00 w95 rFF r01
> CS ON
> rFF w77 w00 w00 w00 w00 w95 rFF r01
> CS ON
> rFF w69 w00 w00 w00 w00 w95 rFF r01
> CS ON
> rFF w77 w00 w00 w00 w00 w95 rFF r01
> CS ON
> rFF w69 w00 w00 w00 w00 w95 rFF r00
> 
> ; Read OCR
> CS ON
> rFF w7A w00 w00 w00 w00 w95 rFF r00
> r80 rFF r80 r00
> 
> ; Read CID
> CS ON
> rFF w4A w00 w00 w00 w00 w95 rFF rFF r00
> rFE
> r03 r53 r44 r53 r44 r35 r31 r32 r57 r50
> r3D r11 r89 r00 r51 r5F rFD rA2 rFF
> 
> ; Read CSD
> CS ON
> rFF w49 w00 w00 w00 w00 w95 rFF rFF r00
> rFE
> r00 r26 r00 r32 r1F r59 r83 rC7 rBE rFB
> r4F rFF r92 r40 r40 r3F rF9 rAF rFF
> CS OFF
> 
> 
> 
> 
> 
> ; *** Initialize a generic 128M SD CARD ***
> 
> VDD OFF
> 
> CS ON
> 5ms
> VDD ON
> 1ms
> CS ON
> rFF rFF rFF rFF rFF rFF rFF rFF rFF rFF
> CS OFF
> wFF wFF
> CS ON
> rFF rFF
> CS OFF
> 5ms
> 
> ; CMD0
> CS ON
> rFF w40 w00 w00 w00 w00 w95 rFF r01
> 
> ; ACMD41
> CS ON
> rFF w77 w00 w00 w00 w00 w95 rFF r01
> CS ON
> rFF w69 w00 w00 w00 w00 w95 rFF r01
> CS ON
> rFF w77 w00 w00 w00 w00 w95 rFF r01
> CS ON
> rFF w69 w00 w00 w00 w00 w95 rFF r00
> 
> ; Read OCR
> CS ON
> rFF w7A w00 w00 w00 w00 w95 rFF r00
> r80 rFF r80 r00
> 
> ; Read CID
> CS ON
> rFF w4A w00 w00 w00 w00 w95 rFF r00
> rFF rFE
> r04 r00 r00 r44 r30 r35 r30 r37 r00 r02
> r02 r8E r69 r00 r48 rFB r6E r4B rFF
> 
> ; Read CSD
> CS ON
> rFF w49 w00 w00 w00 w00 w95 rFF r00
> rFF rFE
> r00 r7F r00 r32 r1F r59 r83 rC9 rF6 rDA
> r3F r9F r96 r60 r00 r2D r76 rB7 rFF
> CS OFF
> 
> 
> ________
> P.S. Resent this message as my SMTP server seems to have a problem.
>