lbenson
Senior Member
Ok. First, I misspoke. I thought I had been running the 14M at 5V, but it was actually 3V3. I switched to 5V, and aside from greater current draw and greater brightness, there was no difference in the ability of the picaxe to light the LEDS repeatedly with no resistors.
And with all LEDs lit:
Here are my measurements of the voltages at 3V3 and 5V with 0V common and with 5V common.
The code, using pinC.0 to select 0V common for LEDs or 5V.
I'm not sure what to make of it all, and I'm not going to quit using resistors. Alleycat's caveat well noted that behavior may well differ between picaxe families (and chip models).
I used these LEDs. The "emerald green" and white ones were quite glaring at 5V.
That works too.since you're in "Destructo Mode" , try tying the anode of the LED to V+ and let the PICAXE sink the current
And with all LEDs lit:
Here are my measurements of the voltages at 3V3 and 5V with 0V common and with 5V common.
Code:
0V common to cathode
at 3V3
orange 1.97
yellow 2.0
bright green 2.7
purple 3.04
white 2.82
blue 2.77
0 milliamps registered on LCD Volts+Current module for any LED; for all (on for 200ms), 44mA.
at 5V
orange 2.0V 45mA
yellow 2.06
bright green 3.24
purple 3.27
white 3.12
blue 3.05
45 milliamps registered on LCD Volts+Current module for any LED; for all (on for 200ms), 101mA.
V+ to LED anode
at 3V3
orange 3.28 to 1.27V 45mA
yellow 1.20
bright green .35
purple .19
white .35
blue .39
67 milliamps registered on LCD Volts+Current module for any LED; for all (on for 200ms), 77mA.
at 5V (measuring 4.84)
orange 2.81
yellow 2.68
bright green 1.30
purple 1.34
white 1.46
blue 1.48
all (on for 200ms), 190mA.
Code:
' 14LEDtest ' runs leds without resistors
#picaxe 14M
w6=30000
if pinC.0 = 1 then
high b.0,b.1,b.2,b.3,b.4,b.5
do
for b1 = 0 to 5
' lookup b1,(5,4,3,2,1,0),b2
lookup b1,(0,1,2,3,4,5),b2
' sertxd(#b1)
low b2
pause w6
high b2
pause 1000
next b1
for b1 = 0 to 9
low b.0,b.1,b.2,b.3,b.4,b.5
pause 200
high b.0,b.1,b.2,b.3,b.4,b.5
pause 500
next b1
loop
else
do
for b1 = 0 to 5
' lookup b1,(5,4,3,2,1,0),b2
lookup b1,(0,1,2,3,4,5),b2
' sertxd(#b1)
high b2
pause w6
low b2
pause 1000
next b1
for b1 = 0 to 9
high b.0,b.1,b.2,b.3,b.4,b.5
pause 200
low b.0,b.1,b.2,b.3,b.4,b.5
pause 500
next b1
loop
endif
I used these LEDs. The "emerald green" and white ones were quite glaring at 5V.
Last edited: