We're using a TWR-K40 Rev C (Sch 26547 REV C) and it looks like the JM40 PTD0:1 is tied to the K40 PTD0:1. Measuring with an ohmmeter, we are seeing 0.4 Ohms. Is anyone else seeing this?
The impedance you are observing in your measurement could easily be provoked by the poor calibration of your ohmmeter or the usage of an improper equipment, according to our calculations the expected impedance is lower than 80m ohms, could you please verify your measurements?
So to get this straight, Are these ports separately controlled, or are they tied together? That's an extremely low impedance to be seeing between two PTD pins on two completely different processors.
Am I missing something? On the schematics, it shows these two points unconnected.With these connected, we can't use some of the output pins and what reason would these points be connected?
80 MOhms or 80 mOhms?
The pins are tied together that is why the impedance is so low, it is a coincidence both pins in the devices are named PTD0, they are independent, the reason for them to be tied is to enable serial communication using the USB connection in case you don't have a TWR-SER board..
According to the schematics, PTD6 and PTD7 are the SCI0 TX and RX pins between the uC UART and the BDM.
The BDM PTD1 and PTD0 are hooked up to the status lights.
My question still holds-- Why am I seeing almost no impedance between the uC lines and the BDM? According to the schematics, they are not connected.
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