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General Category => Discussion - Hardware => Topic started by: bludin on September 15, 2019, 08:50:19 PM

Title: FT232H or FT260 - which chip for USB-I2C(master) bridge?
Post by: bludin on September 15, 2019, 08:50:19 PM
Hello -

For a project that involves configuring and reading out several I2C-sensors from a PC via USB, I'm trying to find the best solution for a USB-I2C(master) bridge. It would be great if the chip also offered >=11 GPIs to read out the INT lines of the sensors (and maybe one GPO to control their RESET lines). As far as I can see, both the FT232H and the FT260 would fit the bill. There seem to be more libraries/support available for the FT232H on the one hand but getting the right driver to install may be a bit cumbersome. On the other hand, the FT260 needs less external components and no low-level driver installation (as far as I understand) but I'm not sure whether an HID device is suitable at all (since I have little knowledge about this) and whether more than one I2C slave can be addressed. Basically, we want to make it as easy as possible for us to develop the hardware, as easy as possible for our customer to develop the software and as trouble-free as possible for the user to install the device. Knowing that this will be a highly specialized low-volume product, what would be your recommendation? 

Thanks a lot in advance,
beat
Title: Re: FT232H or FT260 - which chip for USB-I2C(master) bridge?
Post by: FTDI Community on September 17, 2019, 02:39:45 PM
Hello,

Either of these devices should be a good solution for reading sensors. Do you have any additional requirements such as do the sensors need clock stretching? Also, will you be polling the interrupt lines normally and doing a read over I2C to a sensor when it flags a result being ready?

You can address multiple slaves with either FT260 or FT232H.

As you mentioned, we have a few software examples for the FT232H and it uses our standard FTDI driver. The FT260 uses the Windows HID driver and you can either program with low-level HID request or can use our LibFT260 library in your application to allow the use of more user-friendly calls such as I2C_Write etc.    Which programming language would you be using?

For GPIO, the FT232H would allow the unused port pins to be GPIO (usually up to 12 although some will be output until configured and may need a buffer or series resistor if the sensor will drive a signal in). An I/O expander would be another option and would share the I2C bus.

Best Regards, FTDI Community



 
Title: Re: FT232H or FT260 - which chip for USB-I2C(master) bridge?
Post by: bludin on September 17, 2019, 09:02:40 PM
Our customer who will do the software uses C++ (while we're mostly using Python ourselves for testing purposes mostly).

Among the sensors, there's a number of proximity sensors. Ultimately, they only serve to detect whether a slot is occupied or not. Rather than polling each sensor, this could be read out more elegantly via the INT lines and GPIOs.
You only mention the GPIOs of the FT232H. The FT260 also has 14 DIOs, two of which will be used for the I2C bus, so there should be 12 left that could be used as GPIOs, right?

Thanks a lot for your help.