Need Help in memcpy_P(buffer, CH + 7*c, 7)

Using Arduino LEDs and Multiplexing
1

I am using 8*8 LED Matrix of 5 nos to display text, I followed few instruction from Net,

What does the piece of code indicates

if (*s < 32) continue;

char c = *s - 32;

memcpy_P(buffer, CH + 7*c, 7);

m.writeSprite(col, 0, buffer);

m.setColumn(col + buffer[0], 0);

Where CH stores patterns of character in Flash Memory. What is the meaning of CH+7*c, pls any help

2

It copies 7 bytes from an array CH

    (the elements are 7 bytes in size)

I think the person who wrote that code did try to outsmart the compiler for performance.
3

Thanks for your reply, why it has been checked for <32, what does it indicates, How can Display value of variable 'c' and variable 'Buffer' with in the while loop.

4

I do not have any clue without the whole code

on second thought there might be 32 elements in the array ?

or as you will learn, 32 is a magic bit pattern for text !

5

in the code he has assigned all the letters according to the ascii sequence and from 0 to 31 the letters are not visible....so he has checked weather the letter is visible or not

6