Post Created date
SD Card 5v to 3.3v level shifting for AVR
Rooney, I'm using the SD card module on the right in post 1.  I'll post a scope picture of the clock waveform from the controller at 4MHz when I get the diode adaptor...
Sunday, 14 April 2019 - 17:54
Petit FatFS implementation
Rooney wrote: allano, thank you for this information.  Unfortunately I don't have my project or laptop with me this weekend so I can't reference it.  What I can say is...
Sunday, 14 April 2019 - 15:12
Petit FatFS implementation
    Rooney, I have a couple of questions about the code you are using. 1) Are you using the usi.S file beginning with: I ask because I found the comments in xmit_spi()...
Sunday, 14 April 2019 - 02:23
Petit FatFS implementation
  ka7ehk wrote: I think that F_MCU/2 is the absolute maximum SPI clock rate for a master AVR Mega/Tiny. I typically run half that to be safe. I use an older version of FatFs...
Sunday, 14 April 2019 - 00:43
Petit FatFS implementation
Jim, You are absolutely correct.  I was surprised when I saw so many cycles on the scope and was not careful measuring one cycle because I was more interested in other...
Saturday, 13 April 2019 - 20:51
Petit FatFS implementation
Got the SPI interface to work last night in an isolated project. Wish I could tell you why it now works because I did not run an "as-is" test ...
Saturday, 13 April 2019 - 13:20
Petit FatFS implementation
clawson wrote:No clock on SPI is usually the classic SS thing (or is this AVR not afflicted by that? )   In this case, the SPI interface is created by software and no Slave...
Friday, 12 April 2019 - 15:08
Petit FatFS implementation
  Rooney wrote: So you're not getting any output on the SPI Clock?  I know it's basic but have you made sure it's configured as an output?  I tried a 10k pullup on...
Friday, 12 April 2019 - 13:25
Petit FatFS implementation
I checked the DO output of my SD socket module with a card in it by plugging its CS line into 3.3 volts and gnd.  It stayed high for both states.    I put...
Friday, 12 April 2019 - 02:28
Petit FatFS implementation
Petit FF has a similar delay in avr_mmcp.c for (tmr = 10000; tmr && send_cmd(cmd, 0); tmr--) dly_100us(); /* Wait for leaving idle state */ if (!tmr || send_cmd(CMD16,...
Thursday, 11 April 2019 - 12:09
Petit FatFS implementation
Rooney, I just re-read Chan's article about How to Use MMC/SD to learn what SPI mode to use and noticed his comment that the SD Card's DO line must have a pull up...
Thursday, 11 April 2019 - 03:10
Petit FatFS implementation
clawson wrote: One possible approach is to do the work on a "big" AVR where you can initially get FatFs rather than Petit working and just use that to verify all the hardware...
Wednesday, 10 April 2019 - 18:54

Pages