I'm working on a project that needs a CIS sensor All I can understand that this sensor output an analogue signal that I take on ADC & store the data & process on it . I will use this ROHM module http://www.rohm.com/products/module/image_sensor_head/ . Also after searching I found a lot of chips for the analogue output processing like LM98714 , do I really need one of these or I can just use ATMEGA 8 ADC ??

Thanks in advance .

Please if you need any information mention me .

  • \$\begingroup\$ possible duplicate of Contact image sensor CIS - Concept undersatnding \$\endgroup\$ – Kellenjb Feb 1 '12 at 4:00
  • \$\begingroup\$ It looks like you have done some more research into your project, but you are still struggling with the concepts of how it works. As far as I can tell, this question is the same as your previous, just coming at it from a different angle. \$\endgroup\$ – Kellenjb Feb 1 '12 at 4:03

The typical clock frequency mentioned in the datasheet is 8 MHz. I haven't used an ATMega but I expect the onboard ADC has a maximum rate of < 1Msps.
You could probably drop the frequency but then your scanning would be slow. The datasheet doesn't mention minimums/maximums, so I'd be wary of doing anything other than what it does mention (not a lot) without confirming with Rohm. Maybe there is a separate app note that covers this stuff.

Anyway, you would be best off with a flash ADC with parallel interface, and a uC fast enough to read it comfortably (say at least 20 MIPS, maybe with a parallel port peripheral/DMA)
The datasheet gives no info in the analogue output quality, but I wouldn't expect it to be great so an 8/10 bit ADC will probably be suitable.
Then it looks like a simple case of pulse the SP input, wait 65 cycles and read just after the negative edge for 144 cycles. You may need an inverter with a slight delay (low pass RC would probably do to trim) on the ADC clock if it samples on the rising edge and you are driving both ADC/Module from same output pin.

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