AND Bitwise SPI question

hi guys!,

trying overcome awkward n00b-phase, have question bitwise magic came accros in sketch used read eeprom through spi bit banging. here piece of code:

code: [select]

int read_8(int address)
{
char bit;
char inbit;
char index;
int value = 0;
chip_select_low();
send_8(read);
send_address(address);
for(index = 0; index < 8; index++)
{
bit = digitalread(from_data_out);
inbit = bit & 0x01;
if(inbit == 1)
{
value = value + (0x80>>index);
sclk();
}
else
{
sclk();
}
}
chip_select_high();
return value;
}

if i'm right piece of code reads out byte bit bit starting msb , ending lsb. think understand code except line:

code: [select]

inbit = bit & 0x01;

why line nessecary? can't 'bit' variable not used directly following if-statement?

i hope can give me explanation

cheers!

quote

why line nessecary? can't 'bit' variable not used directly following if-statement?

digitalread return either high or low. high defined 1 , low defined zero. line "inbit = bit & 0x01;" make inbit indeed 1 or 0. since know bit either 1 or 0, isn't needed , use "bit" directly suggested.

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