Pyboard debugging while embedded: powering
Posted: Mon Feb 05, 2018 3:34 pm
Hello,
we have to embed a pyboard into a dedicated board that will feed power to the V+,GND pins of the Pyboard. With the Pyboard powered in such way, I may need to hot-connect via USB to see what's going on from my PC via Putty (and eventually update my Python code) then reset and hot-disconnect when done. If I understood correctly the positive rail of USB is protected by a diode so that, in case V+ is higher than Vusb, there is no current going back to the usb port. For the same reason I will place a diode on the V+ rail:
1. Any advice for the diode to use (type, current, ...) ?
2. Since such diodes configuration will act as a diode-OR, do I need to pay attention to the voltage difference V+ Vusb to ensure that the host PC will "see" the pyboard (as an example let's see three cases: V+=3,7 V+=5 V+ = 6 with V+ measured before the diode drop)
3. If the board designer asks for power requirements, what V+ should I ideally ask (and current..) ?
3. Do you see a cleverer way to accomplish the task ?
Thanx
we have to embed a pyboard into a dedicated board that will feed power to the V+,GND pins of the Pyboard. With the Pyboard powered in such way, I may need to hot-connect via USB to see what's going on from my PC via Putty (and eventually update my Python code) then reset and hot-disconnect when done. If I understood correctly the positive rail of USB is protected by a diode so that, in case V+ is higher than Vusb, there is no current going back to the usb port. For the same reason I will place a diode on the V+ rail:
1. Any advice for the diode to use (type, current, ...) ?
2. Since such diodes configuration will act as a diode-OR, do I need to pay attention to the voltage difference V+ Vusb to ensure that the host PC will "see" the pyboard (as an example let's see three cases: V+=3,7 V+=5 V+ = 6 with V+ measured before the diode drop)
3. If the board designer asks for power requirements, what V+ should I ideally ask (and current..) ?
3. Do you see a cleverer way to accomplish the task ?
Thanx