small updates for next BBB PCB.

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bperrybap
Posts: 42
Joined: Wed Jun 03, 2009 3:17 am
Location: Dallas, TX

small updates for next BBB PCB.

Post by bperrybap » Mon Aug 31, 2009 8:32 pm

Paul,
I have to say I love the BBB board. From the nice light PCB color with the easy to read
labels to its ease of use for prototyping.

If you ever do respin the BBB board for some reason, here are a few tiny things that perhaps
might be worth considering.

- Make ISP power line larger
In some cases it may be desirable to power the BBB board from the ISP connector.
To accommodate this, the trace from pin 2 on the ISP connector probably needs
to be a bit fatter.

- Make the holes for reset capacitor slightly larger.
Since the BUB board already has an inline capacitor, the capacitor on the BBB
board isn't needed when the BUB board is used. If you want to use DebugWire on the BBB
board, you don't want the capacitor. So what I did on my BBB board was insert a 2 pin
header in place of the .1 uf capacitor. I can then use a jumper to connect the reset line
to the 6 pin header or disconnect it. The only problem was that the holes used for the
capacitor are just a bit too small for a header and had to be enlarged a bit.

-An alternate choke and orientation
While I actually thought soldering the surface mount choke was kind of fun as it
was something new to me, it might be a barrier for some. As an alternative
it should be possible to use an inline choke - the same form factor as a resistor.
While there probably isn't enough room to use one in a "normal" horizontal position, there
should be plenty of room to use one in a vertical position. It might even be possible
to create a dual stuff option where you could use a surface mount or a through hole
inline choke in a vertical position.

- Label on 3 pin power sector header
Starting on Rev E, the power selector header no longer feeds the selected power source
to the regulator but now selects where the power comes from.
Perhaps, for clarity it might make sense to change the label "EXT" to "VReg"/"VREG"?

--- bill

paul
Site Admin
Posts: 706
Joined: Mon May 12, 2008 4:19 pm

Re: small updates for next BBB PCB.

Post by paul » Wed Sep 02, 2009 9:58 am

Thanks for the tips bperrybap,
- Make ISP power line larger
In some cases it may be desirable to power the BBB board from the ISP connector.
To accommodate this, the trace from pin 2 on the ISP connector probably needs
to be a bit fatter.
This seems easy - I guess I'll make a file with proposed changes for next respin
- Make the holes for reset capacitor slightly larger.
Since the BUB board already has an inline capacitor, the capacitor on the BBB
board isn't needed when the BUB board is used. If you want to use DebugWire on the BBB
board, you don't want the capacitor. So what I did on my BBB board was insert a 2 pin
header in place of the .1 uf capacitor. I can then use a jumper to connect the reset line
to the 6 pin header or disconnect it. The only problem was that the holes used for the
capacitor are just a bit too small for a header and had to be enlarged a bit.
Likewise - this seems easy - FWIW the cap is in there for legacy compatibility with the FTDI cable.
I don't see too many people using this as a debugging header however.
-An alternate choke and orientation
While I actually thought soldering the surface mount choke was kind of fun as it
was something new to me, it might be a barrier for some. As an alternative
it should be possible to use an inline choke - the same form factor as a resistor.
While there probably isn't enough room to use one in a "normal" horizontal position, there
should be plenty of room to use one in a vertical position. It might even be possible
to create a dual stuff option where you could use a surface mount or a through hole
inline choke in a vertical position.
When I decided to include inductor I looked around for a small unit and also the right price and didn't find any through-hole parts that fit the bill.

- Label on 3 pin power sector header
Starting on Rev E, the power selector header no longer feeds the selected power source
to the regulator but now selects where the power comes from.
Perhaps, for clarity it might make sense to change the label "EXT" to "VReg"/"VREG"?

That one's a tough call - EXT is kind of easy to decode - VREG isn't going to make sense to a lot of newbies unless they go to the schematic.

Paul

bperrybap
Posts: 42
Joined: Wed Jun 03, 2009 3:17 am
Location: Dallas, TX

Re: small updates for next BBB PCB.

Post by bperrybap » Wed Sep 02, 2009 1:23 pm

paul wrote:
When I decided to include inductor I looked around for a small unit and also the right price and didn't find any through-hole parts that fit the bill.
I understand, as this is a cost sensitive product. But perhaps it could be an order option where you
charge say an extra $1.00 for those that want the "easier to solder" inductor.
I think you have something similar for a larger Voltage regulator.

--- bill

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