A
aalex
- Jan 1, 1970
- 0
Hi !
I am trying to drive 16 LED using a microcontroller and two 74HC595N
shift registers. It didn't get to control a single LED so far. When I
upload the code, the LED become either HIGH or LOW, but I can't
control them.
Below is a pseudo-code of the actions executed by the microcontroller.
Everything seems to wired correctly, but it still doesn't seem to
work. I need to drive some LED with that. I tested the output with a
multimeter, and every pin out stays at HIGH (5V). I wired everything
like in this circuit : http://www.ucapps.de/mbhp/mbhp_doutx4.pdf The
microcontroller receives the data well : I can verify it.
Everything seems ok :
* The "output enable" pin is active (LOW).
* The "master reset" pin is inactive (HIGH).
* I need to power LED that need 30mA : this could be an issue, but
still, the multimeter tells me that there is no fluctuation in the
output voltagee of every shift register in my circuit.
Here is the pseudo-code :
set the "storage register clock input" pin to LOW
for each register's output pin from 0 to 15 do: (I use two shift
registers)
set the "serial data input" pin to some value
set the "shift register clock input" pin to LOW
set the"shift register clock input" pin to HIGH (this clock pin is
low-to-high triggered)
set the "storage register clock input" to HIGH (this clock pin is low-
to-high triggered as well)
Anything wrong with this algorithm ? Someone can point me to an error
I might have committed.
Thanks a lot !
alexandre
I am trying to drive 16 LED using a microcontroller and two 74HC595N
shift registers. It didn't get to control a single LED so far. When I
upload the code, the LED become either HIGH or LOW, but I can't
control them.
Below is a pseudo-code of the actions executed by the microcontroller.
Everything seems to wired correctly, but it still doesn't seem to
work. I need to drive some LED with that. I tested the output with a
multimeter, and every pin out stays at HIGH (5V). I wired everything
like in this circuit : http://www.ucapps.de/mbhp/mbhp_doutx4.pdf The
microcontroller receives the data well : I can verify it.
Everything seems ok :
* The "output enable" pin is active (LOW).
* The "master reset" pin is inactive (HIGH).
* I need to power LED that need 30mA : this could be an issue, but
still, the multimeter tells me that there is no fluctuation in the
output voltagee of every shift register in my circuit.
Here is the pseudo-code :
set the "storage register clock input" pin to LOW
for each register's output pin from 0 to 15 do: (I use two shift
registers)
set the "serial data input" pin to some value
set the "shift register clock input" pin to LOW
set the"shift register clock input" pin to HIGH (this clock pin is
low-to-high triggered)
set the "storage register clock input" to HIGH (this clock pin is low-
to-high triggered as well)
Anything wrong with this algorithm ? Someone can point me to an error
I might have committed.
Thanks a lot !
alexandre