Options
i/o address explanation
i am having somewhat of a hard time w/ i/o addressing and the memorization involved. i was wondering if someone could plz explain how they came upon this numberletter combo? i understand hexadecimal and i have the irq down pretty well but i need to know why they are labeled this way. btw i am taking the core on laborday and i already passed the os part but it wasn't by much...lol...i made it to question 30 if that means anything, but my book is a pathetic resource...thx
Comments

Optionsjrowe Member Posts: 83 ■■□□□□□□□□every device in the pc has an address so the cpu can talk to it.
that address is 16 binary digits long
now if you understand hex you can see that 16 binary digits break down into 4 lots of 4
i.e. 1111 1111 1111 1111
4 binary digits being equal to 1 hex value
i.e. binary 0000=hex 0
0001=hex 1
1010=hex A
etc. etc. covering the 16 possible combinations
all devices use more than one address, so a range is specified
i.e. com 1 = 03F803FF
to write that down in binary would be 32 digits long 
Optionsjony265 Member Posts: 8 ■□□□□□□□□□what i don't understand is how it goes from 1010=hex A
what is the formula for that?
btw...thx for quick reply 
Optionsjrowe Member Posts: 83 ■■□□□□□□□□binary  base 2 numbering system
decimal  base 10 numbering system (the way we count)
hexadecimal  base 16 numbering system
binary  hex
0000 = 0
0001 = 1
0010 = 2
0011 = 3
0100 = 4
0101 = 5
0110 = 6
0111 = 7
1000 = 8
1001 = 9
1010 = A
1011 = B
1100 = C
1101 = D
1110 = E
1111 = F 
Optionsjony265 Member Posts: 8 ■□□□□□□□□□ok WOW thankyou sooo much...now i can reason and understand this labeling system it won't be hard to remember(no need to memorize) thx alot