SD CARD CCS C

[temtronic]

it's because you MUST fix the hardware !
You must install 'logic level ' translation between the SD device and the PIC.
As Mr. T has pointed out the 3v SD can't send a '1' to the 5 v PIC.
NO code you try will work.

You must correct the hardware first THEN the software will work....

[Ttelmah]

Critical difference.

If you look at the SD module he is using there, it has level translator
hardware feeding the SD signals.The chip on the right (U1), has the
resistors necessary to pull up the SD lines, and this chip is level shifting
the signals for the SD. This is a properly designed module to drive an SD
from a 5v processor.
The LCD board you have does not have this level shifting. If you enlarge
the picture, you can see that the SD signals go directly to the connector pins.
No level shifting. Hence it _wiill not work_ (with a PIC).
The module he is using is this one:
[url]
https://www.switchelectronics.co.uk/products/micro-sd-card-mini-tf-reader-module?currency=GBP&variant=45334952280373&utm_source=google&utm_medium=cpc&utm_campaign=Google%20Shopping&stkn=bbf1d20e1ed7&gad_source=1&gad_campaignid=20470999819&gbraid=0AAAAAqEgT0CyMF-25WdEaLvA6rjxVP_Wh&gclid=Cj0KCQjwmqPDBhCAARIsADorxIZrqT-NdxVCAXBV5bapVpWcNwJ4IRAveNBVq68KcF-ezTsJQVbY0WEaAtS_EALw_wcB
[/url]

It is rather like putting diesel in a petrol car. Will not work, and can cause
damage.

As Jay says, you need to get the hardware right first. Software cannot fix
incorrect hardware. You can either add your own level translation
hardware, or switch to a module that does have this.

[ilker07]

[Ttelmah]

No.

If you get the picture of the back of the board for that, the connections
to the SD card, just run directly to the pins. No level translation at all.
The SD card interface in the link I sent, has the IC on it to do the level
translation.

[ilker07]

[ilker07]

[temtronic]

You power the PIC with 5 volts, but the SD chip runs at 3 volts.

The SD chip can only give 3 volts for a '1' (high) BUT the PIC requires 5 volts for a '1'(high).

The PIC will NOT see ANY 'high' levels from the SD chip.

This is why you need 'logic level' convertors or translators'.They WILL change the 3 volts '1' signal from the sd chip into 5 volts that the PIC requires.

[ilker07]

[ilker07]

[Ttelmah]

Read the sticky at the top of the forum about this.
SPI, actually _requires_ the high level of the signals goes to 0.8* the
supply. So for the PIC 4v. A lot of chips do not implement this, so will
accept 3.3v. The PIC though does. The device you are showing does
not have the level translation to convert the SD card signals to suit
the PIC. The little SD card adapter used in the example you pointed to
does have this translation.
The code is never going to work without this.
No amount of fiddling is going to make it work until this is fixed.

[ilker07]

RC3, RC4 ==> 0.7 VDD

I think this the problem these pins accept at least 3.5 v

[ilker07]

but it says On-board 5V/3.3V level shifting IC, compatible with 5V/3.3V operating voltage. It has to work???

[temtronic]

please post a link or product info of the LCD/SD module.
Many makers LIE about the 'level shifting'. Really need to see the ACTUAL schematic of the PCB to understand why ,but I suspect they're really saying 5 volts can't destroy the 3v SD chip onboard.

BTW the Arduino uses a different 'tech' under the epoxy than PICs do

[Ttelmah]

The board has a 3.3v regulator to run the SD, but does not have level
shifting to the SD card. I looked at the image and you can see the tracks
go directly to the connector without level shifting.
The PIC is one of the few processors that insist on proper SPI signal
levels. This board will not work without added shifters.

[ilker07]