Re: PCB v3.3a
Posted by Seth on Feb 29, 2016; 2:48pm
URL: http://bluesaab-forum.90.s1.nabble.com/PCB-v3-3a-tp222p251.html
Sorry for the lack of BOM update; that totally slipped my mind
I just updated the BOM.
The Revision resistor (R13) and R14 are irrelevant right now; they haven't been implemented in code yet (that I know of). They are for future use, for software to be able to read the voltage level of that resistor divider network, and let the software make changes as necessary per that pcb. So for example, if (when?) v3.4 of pcb comes out and we had to make a change, the software can poll pin A1, and if it reads a specific value, turn a pin high, vs if it reads a different value, turn a pin low. So right now you don't need to populate R13 or R14.
For C10, it should be 0.1uF and R15 is 10k, but again, these aren't being used (yet) in software, but they will be soon; this resistor/capacitor (RC) network is used to generate a clean 3.3v signal out from the 328 digital 9 pin, to turn on the RN52 Enable pin. without this, the RN52 will never turn on. So without a software update (and C10/R15), the v3.3A pcbs won't work (don't worry, Karlis is on it :)
In the meantime, you can always short the PWREN pin to the 3.3 line to force the RN52 to always being on (which is what all other pcb revisions do right now).
URL: http://bluesaab-forum.90.s1.nabble.com/PCB-v3-3a-tp222p251.html
Sorry for the lack of BOM update; that totally slipped my mind
I just updated the BOM.
The Revision resistor (R13) and R14 are irrelevant right now; they haven't been implemented in code yet (that I know of). They are for future use, for software to be able to read the voltage level of that resistor divider network, and let the software make changes as necessary per that pcb. So for example, if (when?) v3.4 of pcb comes out and we had to make a change, the software can poll pin A1, and if it reads a specific value, turn a pin high, vs if it reads a different value, turn a pin low. So right now you don't need to populate R13 or R14.
For C10, it should be 0.1uF and R15 is 10k, but again, these aren't being used (yet) in software, but they will be soon; this resistor/capacitor (RC) network is used to generate a clean 3.3v signal out from the 328 digital 9 pin, to turn on the RN52 Enable pin. without this, the RN52 will never turn on. So without a software update (and C10/R15), the v3.3A pcbs won't work (don't worry, Karlis is on it :)
In the meantime, you can always short the PWREN pin to the 3.3 line to force the RN52 to always being on (which is what all other pcb revisions do right now).
NC, USA
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