dot matrix 8x8 programming help

[lake]

hi ive coded a dotmatrix (8x8) but i programmed it as both colunm and row that i want to turn on is a 1 and of corse we need one 0v to turn the led on so ive been chaging it but ive some how confused my self about it im using the 40x1 16 outputs 8 for the row and 8 for the colunms so now my problem if i want the first led to ligh up top left row 1 wil postive and colunm 1 is negative
main:
do
let pins=%10000000
let dirsc=%11111111
let pinsc=%????????
pause 1
loop
on the line is my prolem what code would i put there if i do
let pinsc=%10000000
it would mean the they both are posotive and the led will not light so then if i do
let pinsc=%01111111
does this mean that only the first led would light or all of them thanks

Edited by - lakey009 on 11/07/2007 18:13:28

 

[hippy]

With your LED's such that the anodes are connected to PINS then %10000000 will put +V on only one column of LED's. Correspondingly, with the cathodes ( pointy-ends ) connected to PINSC the %011111111 will put 0V only to one row. For one LED it will have its anode to +V and its cathode to 0V so current will flow through it and it will light. The rest will either be across lines of the same voltage so no current will flow or reverse-biased so no current will flow there either, and no others will light.

The easiest way to see it working is to draw out a small ( say 3x3 ) LED matrix and set the rows and columns in this way, then trace current flow and mark where it flows from +V to 0V and lights a LED and where it is blocked.

 

[lake]

oh yes sorry no i was thinking as if the current would flow both ways through the led but it flows once lol silly me got a bit ahead of myself lol srry thanks for help

Edited by - lakey009 on 11/07/2007 18:39:28