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September 8, 2012
about 6 months ago
Indeed. They make the development tools cheap, so that you (or your company) are more likely to spend the big bucks when it comes to ordering components (their bread and butter) in high quantities. For SF, these types of things are their livelihood, so why shouldn’t they make money on them? Even if you just look at it as a way of subsidizing the work they do in support of the maker community, it’s still worth more than they charge in a lot of cases. I owe them thousands just for the time their Eagle and code libraries have saved me!
about 9 months ago
The PCF8575 only tolerates inputs at +0.5 Vdd, whereas the PCA9555 is tolerant to 6 volts, regardless of the supply. This means you can use it in mixed supply systems without level conversion. The 9555 also has more available total sink current, 200 mA compared to the 8575’s 100 mA, while the 8575 has a lower supply current.
Another important note is that the 9555 has true bidirectional IO, which is selectable via a control register. The 8575 is quasi-bidirectional, which can cause issues when attempting to apply voltage to a pin configured as a low output.
Check out Philips app note AN469 for a ton of great, readable information on the differences between various I2C I/O parts.
about 10 months ago
AVNET lists it, but isn’t stocking yet, showing a 6 week lead time. I may ask our rep next time they come around, but I’m going to lead more towards a delay in distribution as opposed to any legal issues.
about a year ago
Which also gives us tons of options for breakout boards. Searching eBay for 2x20 breakout gives several header to screw terminal options for under $20. Very cool!
about a year ago
You must not understand the purpose and uses of LabVIEW and the DAQ units. It is an extremely powerful engineering tool set, one that I use extensively at my school and my job. If you can build a comparable hardware and software package in less than a week, with nothing but hobby know-how and an eight bit microcontroller, I will gladly purchase it from you.
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