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Electronics => Electronics => Topic started by: Webbot on July 05, 2009, 07:47:55 PM

Title: USB to I2C/SPI/UART etc
Post by: Webbot on July 05, 2009, 07:47:55 PM: Apologies to those who read Elektor magazine.

Thought it may be worth publicizing these chips as they are kinda cool.

Available from 'mouser' in US or 'farnell' in UK.

They basically allow USB to anything - be it UART, I2C, SPI etc - the 'expand IO USB' chip being the most flexible.

So if you want to use I2C, SPI etc in your designs and want to control or debug from a PC then they seem ideal.

PS I have NO business interest - and there may well be other/better/worse solutions out there. Just passing on what I've found.

http://www.hexwax.com/products.aspx (http://www.hexwax.com/products.aspx)

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Title: Re: USB to I2C/SPI/UART etc
Post by: galannthegreat on July 05, 2009, 07:49:51 PM: I've been looking for something like this, thanks!
Title: Re: USB to I2C/SPI/UART etc
Post by: Razor Concepts on July 05, 2009, 08:27:58 PM: Looks useful, but pricey... the DIP version is $9. But from reading the datasheets - is it just a specially programmed PIC?
Title: Re: USB to I2C/SPI/UART etc
Post by: Webbot on July 05, 2009, 08:56:40 PM: Quote from: Razor Concepts on July 05, 2009, 08:27:58 PM
Looks useful, but pricey... the DIP version is $9. But from reading the datasheets - is it just a specially programmed PIC?

Well maybe - but if you want to debug an I2C or SPI slave device then its good to use something thats proven. Sure - we can all write it ourselves - but only AFTER we know what we are doing!! Its really hard to write this stuff if you don't have an I2C, or SPI, compliant device to test against.

Not sure if you are talking about the more flexible IO expander or not - when you mention $9. But that is a very flexible device and one you would breadboard for debugging usage and use another hardware implementation on your own board once debugged.

I see it as:- buy, breadboard, debug, learn and then build something more dedicated. So I would use it as a development/debug helper.

But hey - this was just an 'advertisement' - I have no knowledge and no experience of it for now.

If anyone gives it a go then let us know.
Title: Re: USB to I2C/SPI/UART etc
Post by: chelmi on July 06, 2009, 10:07:38 AM: http://hackaday.com/2009/06/25/how-to-the-bus-pirate-v2-with-usb/ (http://hackaday.com/2009/06/25/how-to-the-bus-pirate-v2-with-usb/)

This looks nice. I think it's going to be sell by SeedStudios.
Title: Re: USB to I2C/SPI/UART etc
Post by: sonictj on July 06, 2009, 12:23:20 PM: With a usb to spi chip couldn you essentially program mcu's via isp without the need for a hardware programmer?
Title: Re: USB to I2C/SPI/UART etc
Post by: GearMotion on July 06, 2009, 12:25:34 PM: Quote from: sonictj on July 06, 2009, 12:23:20 PM
With a usb to spi chip couldn you essentially program mcu's via isp without the need for a hardware programmer?

Yes. I've programmed ATtiny chips (tiny13, tiny26) using the USBmicro U401/U421: http://www.usbmicro.com/products.html (http://www.usbmicro.com/products.html)
Title: Re: USB to I2C/SPI/UART etc
Post by: Webbot on July 06, 2009, 07:44:13 PM: Quote from: sonictj on July 06, 2009, 12:23:20 PM
With a usb to spi chip couldn you essentially program mcu's via isp without the need for a hardware programmer?

Think the only difference is that the SPI chip select pin needs to go the RESET pin on the processor when used for programming