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I feel a bit like I'm losing it... I can't seem to find a (modern) i2c counter chip. Something that will take random events, sum them up, and let me poll from a uC a couple times a second. Events can be minutes apart or in the 100khz range.

I'm trying to design a modular board that will interface with the main uC. This modular board is fairly simple but the variants on the end application can make it quite different.

I understand this tends to be done directly on a uC but I'm looking for something that lends itself to production (small-medium scale). I'm trying to avoid extra programming steps (just for a counter) on our production. Oh, and also low power ;P

I've thought about misusing a RTC chip but that doesn't seem sound for production and I really don't need a xtal front end.

Any thoughts?

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    \$\begingroup\$ the programming steps are unavoidable \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Sep 22 '16 at 22:13
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    \$\begingroup\$ @TonyStewart unavoidable yes, but delegable - the microcontroller vendor or a distributor such as DigiKey can perform them for you and ship you programmed ICs. \$\endgroup\$ – pericynthion Sep 23 '16 at 5:58
  • \$\begingroup\$ yes anything can be a make or buy, even hiring programmers online here (not me), I didn't know D-K had programmers but possibly have contractors to do it. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Sep 23 '16 at 6:03
  • \$\begingroup\$ The design really isn't the problem. I'm quite capable of setting up the uC solution (its currently my alternative). Main problem is just the volumes, this might do 1-2k a year. Which always ends up in that weird middle ground of it makes sense to get custom stuff from mfg. but the volume isn't quite high enough to get the price down... \$\endgroup\$ – user3219864 Sep 23 '16 at 13:57
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There is no shortage of small microcontrollers that have both:

  1. Digital counter.
  2. Built-in hardware I2C peripheral that can act as an I2C slave.
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  • \$\begingroup\$ I know thats an option, but it just doesn't quite make sense to me since you can get i2c GPIO, ADCs, DACs, Clocks, etc. and most uC's have those built in also. So yeah part of market demand and all, just seems a little oddball.... \$\endgroup\$ – user3219864 Sep 23 '16 at 13:51
  • \$\begingroup\$ By the way, we had a similar (perhaps even duplicate) question a few years ago: I2C-controlled digital counter. \$\endgroup\$ – Nick Alexeev Sep 23 '16 at 20:41
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The PCF8593 is designed to optionally count events on a pin instead of time on a crystal.

From the NXP Semiconductor data sheet for the part:

enter image description here enter image description here

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  • \$\begingroup\$ Please add the important details to your simple answer, or it will get little attention or votes. \$\endgroup\$ – Sparky256 Jan 8 '18 at 4:57
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If you have to have an off board solution with timing. Use a CPLD, then you can get what ever logic you want. The design complexity goes up, but you will save power. Price starts at ~1.5 with quantity.

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  • \$\begingroup\$ This does not avoid a programming step. You'll be programming a CPLD instead of a MCU, but that does not simplify OP's production process (which is what he wants in the end). \$\endgroup\$ – dim Sep 23 '16 at 7:35
  • \$\begingroup\$ Yeah, our production process is really the main problem with this particular issue. But I don't have the authority to fix that.... :| \$\endgroup\$ – user3219864 Sep 23 '16 at 13:53
  • \$\begingroup\$ Why doesn't it? One can get programmed CPLDs from the factory, no need to program, just solder them to the board. \$\endgroup\$ – Voltage Spike Sep 23 '16 at 15:52
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Looks like you're right. There seems to be no i2c-enabled binary counters on the market. Probably because of cheap uCs and CPLDs that can do the job. However, if you want, you may still use a simple binary counter like SN74LV connected to an I2C GPIO expander like XRA1203 (I like these because they are very versatile and configurable) to build an "i2c-enabled binary counter". This, however, will cost you more than a CPLD.

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