You're correct about the rest of your options if you must run at 8MHz, you can use the internal 8MHz source (requires new fuse bits) or divide the external source using the prescaler (requires changing a register). Although this is technically outside the guaranteed safe envelope, these chips tend to have a bit of margin built into them to tolerate manufacturing variations. One option at this point is to keep running it at 16MHz (and choose "5V/16MHz" in your IDE so the timing is right). If you have a 3.3V supply, you can certainly feed that into VCC and run the board at 3.3V. The ATmega itself will happily run at either 5V or 3.3V. The only differences between the two boards are the voltage regulator and the external oscillator (sorry, and the bootloader). Sadly the problem is outside of my skill level. I would love to see someone fix this issue. If you try to communicate with multiple devices within a single scan cycle the system will freeze.Īlso with any noise on the vcc line the reliability drops significantly. i used one byte of data to one device per scan cycle of the arduino. the communications i was using was fairly simple. High data traffic is also a major problem. The original version of the file with timeouts works best for slave devices. I managed to get a working version of the library with a modified the twi.c file for the master devices only with timeouts and a bus reinitialize inserted into the "never ending" while loops. To be quite honest, there are a lot of bugs in the official version of the Wire library and in the end I've had to use 2 different modified versions of the TWI.c that steamed from this forum: Just a heads up, I've been fighting with the Wire.h library for the past month. Note: A portion of this sale is given back to Arduino LLC to help fund continued development of new tools and new IDE features. The latest and greatest version of this board breaks out the ADC6 and ADC7 pins as well as adds footprints for optional I2C pull-up resistors! We also took the opportunity to slap it with the OSHW logo.Ĭan't decide which Arduino is right for you? Arduino buying guide! If you're supplying unregulated power to the board, be sure to connect to the "RAW" pin and not VCC. There is a voltage regulator on board so it can accept voltage up to 12VDC. The Arduino Pro Mini also works with the FTDI cable but the FTDI cable does not bring out the DTR pin so the auto-reset feature will not work. This board connects directly to the FTDI Basic Breakout board and supports auto-reset. In order to accomplish this we used all SMD components, made it two layer, etc. We really wanted to minimize the cost of an Arduino. The Arduino Pro series is meant for users that understand the limitations of system voltage (5V), lack of connectors, and USB off board. It's a great board that will get you up and running quickly. We recommend first time Arduino users start with the Uno R3. Arduino Pro Mini does not come with connectors populated so that you can solder in any connector or wire with any orientation you need. This is a 5V Arduino running the 16MHz bootloader. It's blue! It's thin! It's the Arduino Pro Mini! SparkFun's minimal design approach to Arduino.
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