# LED dot matrix

Discussion in 'The Projects Forum' started by teivel, Jul 9, 2014.

1. ### teivel Thread Starter New Member

Jul 9, 2014
4
0
Hi, my purpose is to find the output of led dot matrix connected to pic16f88 using flowcode V3.6.11.53. This is the led dot matrix im using. I try to light up each col and row first. This is the output i found for COL0-7 (due to using demo version of flowcode, the outputs can be used are limited ). Output for col6 and 7 are 191 and 127. When i try to light up row0 with the output of 254 at port A and 0 Please help

2. ### MrCarlos Active Member

Jan 2, 2010
400
134
Hello teivel

It is difficult to understand your paragraphs In the midst of those gigantic pictures.
Removing them I think this is what you say:

Hi, my purpose is to find the output of led dot matrix connected to pic16f88 using flowcode V3.6.11.53. This is the led dot matrix im using.

I try to light up each col and row first.

This is the output i found for COL0-7 (due to using demo version of flowcode, the outputs can be used are limited ).

Output for col6 and 7 are 191 and 127. When i try to light up row0 with the output of 254 at port A and 0

Do You have the data sheets of the dot matrix ?
Surely therein is described how to handle it.

Let me take the data you mention:
I will assume that the numbers you have are decimal.
For column 7 You have 127.
And to row 0 You have 254.

127 (Dec) = 01111111 (Bin).  column 7.
254 (Dec) = 11111110 (Bin). - row 0.

R7 1
R6 1
R5 1
R4 1
R3 1
R2 1
R1 1
R0 0
CCC 0 1 1 1 1 1 1 1
CCCC7 C6 C5 C4 C3 C2 C1 C0

We need to know if to turn on a column of LEDs, must be low or high.
consequently:
The rows will be the other polarity.

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3. ### teivel Thread Starter New Member

Jul 9, 2014
4
0
hi mrcarlos, sry for posting gigantic pic that make u difficult to read ( didnt expect it would be like this )and i missed something. whn i give output of 254 at port a and 0 at port b, the led at row0 lights up but also led in row5,6 & 7... i dont have data sheet of the dot matrix. btw , when u give output of 127 to port A , the led at row 5,6 and 7 light up together.

4. ### MrCarlos Active Member

Jan 2, 2010
400
134
Hello teivel

Apparently the matrix is damaged.
When the Port A = 254 and Port B = 000, turn ON the rows 0, 5, 6, 7.
When the Port A = 127 and Port B = 000, turn ON the rows 0, 5, 6, 7.
Then rows 5, 6 and 7 never go out ?

You can do an experiment:
Port A = 000
Port B = 254
Then:
Port A = 000
Port B = 127

Notify what happens to the LED matrix please.