Problems with Arduino BT


two questions about Arduino BT (w/ WT11 + ATmega328P):

  1. currently I'm using a bench power supply with current limiter to power Arduino. I set the voltage to 4,7V and the current limiter to 100 mA. Sometimes, the Arduino board (with no external connections) will sink the whole current available at power up. It appears like a short-circuits. I thought it could be the on-board switching that needs more current at start-up. Anyway, also limiting the current at 200/250 mA leads to the same behavior. Anyone else reported this? I'm afraid to power the board with a battery: I could damage it for overcurrent.

  2. I have some difficulties to write a working serial repeater (@ 9600 bps) between Arduino BT and an external board (using NewSoftSerial). So I'd like to use Arduino BT as host PCB for WT11. I'm wondering if I may connect my external serial to TX0/RX0 (used by WT11) setting those pins as input for the Arduino AVR. In this way I can communicate directly with the WT11. Furthermore, if I disconnect the Arduino AVR rtx pins, will the WT11 continue to work, won't it? I'm talking about some "hidden" initializations routines provided by Arduino AVR firmware.


Solved point 2). I added a 4k7 resistor between the input pint of WT11 (RX) and GND because the datasheet says the maximum allowable voltage is Vdd (3v3) + 0,4V. Then, I changed the baudrate of the WT11 using the initialization sketch. After that, I recompiled the bootloader to run @ 9600. Eventually, I set the tx0/rx0 as input and I connected my board there. Now it works like a charm.

Anyway, point 1) is still an issue.