Guru
Joined: 20/06/2011
Location: AustraliaPosts: 2981
| Posted: 04:42pm 23 Jan 2016 |
Hi Circuit,
The specs I have say this pin should be directly connected to 3v2.. (3v3 is close enough) and that it should draw 60-70mA. mine, as Jim stated, has a 3R9 resistor in series..
Using 65mA as the current and wanting to connect to 5V I would use 1.8/.065 = 27ohm...
I am sure that this can be 18 ohm safely and this would draw 100mA.
My backpack170 draws about 80mA with the circuit used and hasn't caused any harm..
Re. the shorting out the Vreg, I have never liked that as I believe that it is to lower the voltage to about 2.1V (or was that 2.8V) for the internal workings of the display module itself. Shorting J1 would put a 3v3 on the `innards' and could be the cause of some of these displays failing..
Regards,
Mick
Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<