I am wondering whether is there available a hardware manual or similar regarding FEZ Cobra III. I got my board but not quite sure f.ex. how to connect I2C, shall I use pull-up resistors, what pins shall I use to bring in analog input (along with voltage pin) etc.
Other suggestion is to bring down WiFi board prize, I mean that Rasperry Pi III support WiFi as build in.
Thank you.
@ jari - You can take a look at the schematic for the FEZ Cobra III, which can be found under the Resources tab on its catalog entry. It is also based on the G120, so the G120 Datasheet (https://www.ghielectronics.com/downloads/man/G120_and_G120E_Datasheet.pdf) is useful and possibly the NETMF manual (https://www.ghielectronics.com/downloads/NETMF/NETMF_for_Beginners.pdf).
In the latest SDK, there is also a class that lists all the pins under GHI.Pins.FEZCobraIII.
@ John - I see a schematic of the G120 rather than the Cobra III.
Doubtful, since GHI don’t release the schematic for the G120?
https://www.ghielectronics.com/downloads/schematic/FEZ_Cobra_III_SCH.pdf accessible from https://www.ghielectronics.com/catalog/product/540 .
It is somewhat confusing since they do slip “Fez Panda III” in there in at least one point, but it is the G120 based Fez Cobra III.
@ Brett - Righto. Took another look and definitely the cobra’s schematic. I saw the G120 label in my small window and did’t see the rest of the schematic.
I’m in need of a 24VDC power supply to run 2 Cobra II plus an actuator valve. The valve draws 0.5A at 24VDC but what do the Cobras draw? And do the Cobra III draw less?
And what size of barrel connectors are on the Cobra II and is the connector on the Cobra III different (for when we upgrade)? Can’t seem to find these figures.
This is very subjective. The total current draw will be determined by how much current is being drawn by what ever the Cobra III is being used to drive. i.e. If used to drive a charlieplexed array of 1000 LEDs, the current draw will be higher than if used to drive 1 led. Unbounded I’d say no GHI module draws more than 0.25 Amps @ 12V.
As for the barrel jack; not sure. However, from since the Fez Domino days the size of the jack has never changed. I believe it is this size:
https://www.sparkfun.com/datasheets/Prototyping/Barrel-Connector-PJ-202A.pdf
Btw don’t try and drive the Valve from the Cobra Pins. Use a power mosfet.
power sockets are standard 5.5mm with 2.1mm pin.
@ Mr. John Smith - Thanks. Yes, i was thinking of unbounded, but even that could depend on ethernet connection draw, onboard ADC use, etc. But in any case, 0.5A for the valve, <=.25A @ 12V for the boards, plus a temperature sensor and a couple LEDs adds to a small load. The drawing for the DC power supply seems like whats on my Cobra II-- 6.5OD, 2.0 OD internal pin and comforting to know things are likely to have not changed.
Thanks Brett. 5.5 x 2.1mm sounds like it fits.