Hi
I have recently used a Pic16F883 to run an LED network 12 by 4 hence 48 blue LEDs.
A 100ohm resistor was used to limit current. fwd volt drop of LED 1.2v, 0402, 5v supply. K8048 vellerman programmer using ICSP.
E.g. A4 is used as the positive supply to 4 LEDs, C0,C1,C4,C5 used as negatives all with 100ohm Res.
Program turns on A4 and then C0,1,4,5 respectively in a loop, A4 remains on, however I have tried clrfPORTA after first loop and back on again to no avail.
I sped up the flash rate from 1/s until the LED appeared to be on, I am not sure what the flash rate is but it's not that fast
All worked well until suddenly C5 used as the open drain or negative side of the LED started staying sort of half on,by this I mean all LEDs in the network that used C5 as their negative stayed on half lit until their turn came up and then illuminated correctly.
My next attempt to reprogram IC is not recognised, presumed blown.
My best guess is that one or more LEDs failing have shorted and blown the IC.
The LEDs were purchased quite cheaply from U.K. Company via China.
Anyone has any ideas would be appreciated.
I have recently used a Pic16F883 to run an LED network 12 by 4 hence 48 blue LEDs.
A 100ohm resistor was used to limit current. fwd volt drop of LED 1.2v, 0402, 5v supply. K8048 vellerman programmer using ICSP.
E.g. A4 is used as the positive supply to 4 LEDs, C0,C1,C4,C5 used as negatives all with 100ohm Res.
Program turns on A4 and then C0,1,4,5 respectively in a loop, A4 remains on, however I have tried clrfPORTA after first loop and back on again to no avail.
I sped up the flash rate from 1/s until the LED appeared to be on, I am not sure what the flash rate is but it's not that fast
All worked well until suddenly C5 used as the open drain or negative side of the LED started staying sort of half on,by this I mean all LEDs in the network that used C5 as their negative stayed on half lit until their turn came up and then illuminated correctly.
My next attempt to reprogram IC is not recognised, presumed blown.
My best guess is that one or more LEDs failing have shorted and blown the IC.
The LEDs were purchased quite cheaply from U.K. Company via China.
Anyone has any ideas would be appreciated.