What MCU offers most input capture channels?

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Hello,

For an array of proximity sensors, I need a microcontroller with as
many input capture channels as possible, so far the best one I found
are some HCS12 devices with eight channels. Is there any other brand
MCU that offers more than this at a competitive price?

Thanks,
Stefan

Re: What MCU offers most input capture channels?
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How many is as large as possible.

With an FPSLIC AVR+FPGA you can do a very large number.
If you assume you want to have 16 bit resolution on the capture,
you can use the internal FreeRAM as capture buffer.

The AT94K05 has 12 small SRAMs which are 32 x 4.
Yuo can thus create a 48 bit wide memory, and use 16 bits
for timer capture and 32 bits for capture.

An edge detector is used on each input, and one bit is stored per sensor.
The FPSLIC runs at 25 MHz, and if you can run the capture at half the
frequency
you can use 2 SRAM words, so you get 80 capture channels.
If you run at 1/4 th frequency, you get 176 channels etc.
Hopefully this is enough.

The SRAM will allow a FIFO function making realtime response less of a
problem.

The contents of the 32 x 48 SRAM can be auomatically copied to a
larger 8 bit SRAM (up to 16 kB)

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Ulf Samuelsson
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Re: What MCU offers most input capture channels?
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There is the ST10/C167 although I'm not sure they are competetive price
wise. The 10F168 has something like 32 capture inputs, and onboard flash
and ram.

Robert

Re: What MCU offers most input capture channels?
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M68332 or other Moto units with the TPU (Time Processing Unit) offer
16 channels of input capture.

Mark Borgerson


Re: What MCU offers most input capture channels?

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I'd consider a CPLD or an FPGA, depending on the number of channels
required. A modern FPGA such as the Cyclone with 59k flipflop up
should support 2000 or so 16 bit counters.

Rene
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Re: What MCU offers most input capture channels?
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Well if you move up to the HC16 devices you get the eight channels
plus it has TPU with 16 channels (with 16 external pins). The TPU is
an generic timing "CPU" thats embedded inside the HC16. Any channel of
the TPU can  be configured to be input capture, so that device will
give you a total of 24 input captures, I'd imagine it would be at a
competitive price too. Next up are the much more expensive 555 (32
channels dual TPU) and 565 (48 channels tri TPU)

Re: What MCU offers most input capture channels?
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Thank you all, I think I will check out the TPU approach. FPGA based
design sounds like a good idea too, but I think the TPU gives the best
price/performance ratio for my application.

Stefan

Re: What MCU offers most input capture channels?
Hello Stefan,

if you really want to go with Freescale, the Power PC based option is
probably the best. If you are looking for the "king of the court",
have a look the Infineon Tricore TC1775. As far as I recall 96 capture
options, may be even more. Both are not exactly easy to use. The
C167CS offers a lot of them as well at least 16. If you have use for
an ADC, the C167CS has 24 inputs as well.

An Schwob

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