Hi, ?I'm new to ATMEL devices.
How does the Xprotolab handle negative input voltages on the ADC input ?
I can see x 0.1 scaling on the input, and the specs say it can handle -14V inputs, but even at x0.1 that will still be a signal of -1.4V into the processor ADc pin ?
I usually use Microchip devices and so Im interested in knowing how Atmel handle this.
Along with having dual 12 bit DACs onboard...I may be a convert.
Thanks,
carloman

Hi!
Alook at the schematics will reveal the "secret"\r\n/ www.gabotronics.com/download/xprotolab/xprotolab-schematics.zip
I am basically shifting the voltage up before entering the ADC.

Hi. /\r\n/OK...I see now that R4 goes to 2.048V.....I had not noticed that before...I thought it went to GND./\r\n/That, along with attenuation allows you to manage that wide bipolar input./\r\n/Very nice./\r\n/Thanks....I am enjoying your products./\r\n/C/\r\n/

Hi, the datasheet states that the absolute minimum voltage on any I/O pin is -0.5V.
The section that you see for -0.1V is the range. The ADC is set on differential mode, so the range for the differential input is -VREF to +VREF. The differential inputs for CH1 and CH2 are (ADC5 pin - ADC6 pin) and (ADC5 pin - ADC7 pin) respectively. VREF is 2.048V.