SD Card chip select while using portG

Projects General Guidance
1

I need to modify existing code to work with an Iteadstudio SD shield 3.0. The existing code uses the bottom 3 bits (0-2) of portG - the SD shield wants to use bit 5 of portG (D4).

The question is how can I find out if the SD routines will modify the portG settings for bits 2-0 ? I.e - Is using PortG bit PG5 likely to influence the existing code that uses PortG bits PG0-PG2 ?
Note: The code will not function if it is not connected to the device it is designed to drive - and running it when modified risks damaging the device. THOUGHTS ??

2

Study the library code. The library will not modify any port bits other than the ones specified for interaction with the target device.

Is using PortG bit PG5 likely to influence the existing code

No, unless the "existing code" uses PG5. If you have questions about code, post the code, using code tags.

3

jremington -

Thanks - HOW do I get access to the library code. I have been unable
to find the *.h files and other library code.

I'm new to this IDE.

Cheers!

Bruce

Quoting jremington via Arduino Forum
notifications@arduino.discoursemail.com:

4

Arduino library source code is almost always posted on Github.

Which Arduino and which SD library are you using?

By the way, D4 is usually SD_CS (chip select) and you can redefine that chip select to use just about any digital pin. The "SD shield" may limit those options.

5

Thanks - I got it to work ONCE. There were two problems. First seemed to be in incompatible (small) SD card - the other needed some board mods to get SD>begin(SD_ChipSelect) fails. Are you willing to take a look at the code to see if you spot anything? Otherwise I will post another question / topic.