Greetings,
Hopefully I posted this to the right forum, but but what options exist to connect a PCA9545A Bus Expander to an I2C device, i.e., breakout boards or chassis?
I didn't see any options on the website.
Thanks!
-J
Hello Jesse,
Not sure what you are asking here. For the PCA9545A there are no EVM boards available. The easiest way would be to get any number of Evaluation boards that have MCUs that support I2C,MSP, Stellars, CC2541, C2000. etc.
You would have to create your own board to interface the PCA9545 to the MCU and any other device that supports I2C. The MCU can have I2C in hardware, or you can generate the protocol using software.
There is also the option of connecting to you printer parallel port or you have one.
Hi greenja,
Thanks for getting back to me! Ok, I was told that I need bus expanders (i.e. the PCA95454) for my application. I thought that when I received the chips, I would be able to hook them into something, like the MSP430 evaluation board. Well that's not the case with this obviously, so I'm looking to see how to connect the PCA95454 to my I2C device, or for that matter, are there any bus expanders out there that exist to interface to an I2C device where I don't have to create my own board?
Well, there are options. You can do a dead bug connection by turning the chip upside down and wiring to the leads, or you can find a board that has traces that match the chip and use it.
As you can see from the images below, I have done both! The PLCC-52 was a prototyping board from the HC11 days. I attached the I2C PCA9555 to the back along with the I2C LSM303DL digital compass and an I2C EEPROM.
It doesn't have to look good, it just has to work!
ps. Once you get the hang of it, you can do even the really fine pitch chips. The trick is to use magnetic wire from a bobbin transformer and just scrape away the coating at the tip with an X-Acto knife. Apply solder to the wire and to the chip leads separately. Then solder the wire to the chip lead. Since both have solder on them, you just have lightly touch the iron to the connection. Use lots of flux. Most importantly make sure your hand is resting on the table and you hold the wire in the center of the chip lead.
pps. A magnifying lens comes in very handy. I use a tube from one of those small binoculars and the lenses at the end. Simply place the lens at the end of the tube and if you need more magnification put them both in. My handy third arm provides the lens holder. Not as pretty as a microscope, but like I said, it just has to work!
greenja,
Ah, great! The pictures helped a lot! Thanks for your feedback!