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Member Since: January 6, 2006

Country: United States

  • What's up with the 16 MHz crystal on these Unos? The picture or the Uno itself doesn't look like it has the standard crystal for the Atmega 328P; was it replaced by a resonator or something similar? (The smaller USB chip seems to have the correct 16 MHz crystal).<br />
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    I ask because code that I had, working with 57600 baud, doesn't work properly anymore. The bytes are corrupted half or more of the time. I had to switch down to 38400 baud. This suggests the crystal/resonator may be less accurate.

  • The internal oscillator isn't as bad as the specs say. I have used it with a 250000 baud Zigbee module several times with no problem. It can also be tuned. It has a lot of jitter, but not enough to matter.

  • This is a common misconception about these connectors. To unplug them, you have to yank hard and quickly. If it's too slow it won't come out no matter how hard you pull on it.

  • The module I just got has power-up pin (23) connected to Vcc, so it is always powered on. But the datasheet shows that there should be another connection broken out for PRU. Does anyone know what to do? I need to be able to go into power-down mode.

  • I've noticed with an oscilloscope precisely this, if you give the transmitter a 1 on its data line, the receiver only receives a pulse, it otherwise constantly outputs 0. A start bit with USART is a high to low transition so I don't know how this would interface with USART. I think it could still work. However the pulse width does not seem to be a constant value, I was getting between 80 to 200 microseconds or so. I'd start with a pretty low baud rate and hope that works...

No public wish lists :(