MicroMod processor card - development questions

Development Boards MicroMod
1

Hi everyone!

I am developing a MicroMod processor card. The ‘Designing with MicroMod’ pages, as well as some forum posts, have been very helpful. But I do have several questions.

The MicroMod Interface Pin Descriptions give a detailed pinout for the M.2 key E card. With regard to the CAN interface on this card, I presume that the intent is for the interface to be used by a CAN controller on the processor, not a controller and a transceiver? Since CAN_RX and CAN_TX are used, it implies to me that the carrier board would house the CAN transceiver. But can you envision a scenario where you’d like the interface at the M.2 card edge to carry the CAN_H and CAN_L signals from a transceiver?

Also, the specs/suggestions mention connecting an on-board status LED to a GPIO port. Is it acceptable to route this through an I2C GPIO port expander, or does it have to be directly connected to the port? I’m trying to economize on ports, and having digital I/O and PWM implemented via expansion ports will be advantageous.

Additionally: it doesn’t seem like the existing processor card designs include ESD protection of any kind. Is this so because it’s assumed that the carrier boards implement surge suppression and ESD mitigation?

Lastly, what’s the intent of the BATT_VIN/3? I understand (?) that this should be routed to a free ADC input so that the processor can read the carrier battery voltage (if any) – but why divide by three? Was this to limit the max voltage to 1V to accommodate certain processor cards?

Thanks for your feedback. I have not experimented with the MicroMod system in person yet, so perhaps these questions would have been resolved had I done so – please forgive the questions of a noob.

2

Addendum: if the intent is to sell a processor board via SparkFun, do the boards need to be certified (for example: Bluetooth & WiFi emissions) if we aren’t using a pre-made module, and if so, what type of certification or testing is required? Or will SparkFun assist with this, and/or offer uncertified products for sale? I’m thinking along the lines of CE, Bluetooth SIG, or FCC certification.

3

The MicroMod processor in that case would be the CAN transceiver.

Either should be fine, I’d think…you can also skip an LED if needed, it’s just nice to have it light up when someone plugs their device in to at least halfway confirm it is working

Yes (about ESD being handled by carrier board components)

I believe bc most chips saturate well below battery voltages; one of our uses a 2v chip (artemis) so we need to divide the max battery voltage of 4.2 or a vin of 5 / 3 to get workable ADC values

No to basically everything in the last paragraph except: pre-certified modules are fine, however trademarks and copyrights in the product description become tricky…bluetooth licensing, etc. But! There are labs you can send it off that handle this sort of thing