Hi all, I'm slowly getting a small board together using the PocketBeagle for logic analysis and stimulus.
For now, my experiments have revolved around powering the device off a USB host, however I'd like to eventually have the board self-powered via a 4-cell lithium battery pack, stepping that down to +5V for Vin. To power USB VBus, I have a Maxim MAX1607 wired up. Currently, I have hooked its nEN pin to 0V, since as far as I know, the V_EN pin on the PocketBeagle is active-high, and my USB chip requires active-low. This is hooked up according to the diagram at https://lh3.googleusercontent.com/-lu0aOUP8tbc/Wg8Z3vezBxI/AAAAAAAAAUQ/ud2QXK4zW9gwIhrqVif5ChtTqCcqjDicQCLcBGAs/s1600/PocketBeagle_microUSB_3.png with one difference, since I initially followed the advice on the FAQ, I have USB1 V_Bus (pin 5) and USB1 V_In (pin 7) bridged. This worked, but I still get some issues with the USB dropping out momentarily, which can be seen on the console. https://hackaday.io/project/28513-electronics-hacker-lab/log/78536-improving-usb1-stability shows the messages that can be seen on the console. I suspect that moving to an external 5V DC supply on the Vin pin of the PocketBeagle will improve this. I don't expect to be driving anything high-current off the GPIO pins, as I know they won't handle it. LEDs would be about as high as I'd expect. Based on this, what current capacity do people recommend for these? I have a stack of Rohm BP5293-50s which are 3-pin switchmode devices good for 500mA: http://www.rohm.com/web/global/products/-/product/BP5293-50 Is 500mA sufficient, or should I aim higher? Other recommendations? The other problem I have is knowing when to kill the power. Is there a pin I can monitor on the PocketBeagle's GPIOs that could tell me when the device has halted? I could configure a GPIO as a "LED" and set it to heartbeat, but that's a messy way to find out if something is down. If there was a pin that went high, or low, when the CPU halted, that'd be ideal, as then I could use that to kill the power. Regards, -- Stuart Longland (aka Redhatter, VK4MSL) I haven't lost my mind... ...it's backed up on a tape somewhere. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/78424c78-22d6-5181-d5b4-49b358593a56%40longlandclan.id.au. For more options, visit https://groups.google.com/d/optout.
