Troy
USA
Asked
— Edited
Another post reminded me of this question I've been meaning to ask. The underside of the EZB has traces near the bluetooth connector that seem to me like a user selectable voltage to the connector. My question is: Can I break the trace for the +5V jumper pad and solder the jumper pad for +3.3V? Also would this change the logic levels on that connector or only change the V+ pin to 3.3V?
There is no way to change the logic levels, as well as there is no reason. As answered in a different thread...
The EZ-B will accept logic to a maximum of 5 volts. Any voltage greater than 0 volts is considered ON. Any voltage referencing GND (zero volts) is OFF.
The pad can be cut on the EZ-B to power +3.3v to the communication header. Additionally, you can get 3.3v from the side header.
Yes that was the thread that reminded me. I understand what you said there on the RX line on the EZB. The reason I ask is about using the Synapse board without a voltage divider. I believe it may not handle 5v pulses to its rx line. :/ Just to be clear, the jumpers only change the V+ on the header and hasn't anything to do with the TX logic level?
Any 3.3v ttl will work with 5v logic. Just power it correctly with 3.3 and the 5v logic ttl will e fine. I've never blown up anything that way. It's because the sink current out of a micro is sooooooo low. Something like 25mha on the ezb micro. :)