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
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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)
-- Best Regard Ulf Samuelsson This is my personal opinion which may or may not be shared by my employer Atmel Nordic AB
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
M68332 or other Moto units with the TPU (Time Processing Unit) offer
16 channels of input capture.Mark Borgerson
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
-- Ing.Buero R.Tschaggelar - http://www.ibrtses.com & commercial newsgroups - http://www.talkto.net
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)
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
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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