0
\$\begingroup\$

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 .

\$\endgroup\$
  • \$\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
2
\$\begingroup\$

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.

| improve this answer | |
\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.