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...
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...
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...
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()...
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...
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...
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 ...
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...
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...
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...
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,...
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...
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...
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