I will say that if you do your homework and choose wiselyyou can save a ton of money and get a quality equivalent or better product/service for less money.
I'm shure because I have some of those pcb's.Micky
On a mostly unrelated note I see that the SainSmart board is advertised as being for IIC / I2C / TWI. For the uninitiated these are three different ways of expressing essentially the same serial interface technique. Now you could construe this two ways so I offer it just as an observation.(1) They are trying to dupe the unwary into thinking that the board can utilize any of three different serial interface techniques.(2) They are trying to help the uninitiated who might not know that they can use the I2C interface even though the manufacturer of their microcontroller called it TWI to avoid a trademark or copyright infringement.[/color]Don
Perhaps the chip has undocumented internal pullups on the address lines?
QuotePerhaps the chip has undocumented internal pullups on the address lines?Wouldn't they then designate the base addresses as 0x27 and 0x3F?Don
It does use the same identical IC to do all the multiplexing, so is it not a simple case of finding which pins they are and getting the soldering iron out?
Are you saying that the A0, A1, A2 pins on the 8574 are not connectedto anything? Did you ohm it out?
A0, A1 and A2 has contact but only to GND.
But, if the chip happens to have internal pullups, it really wouldn't affect the base addressit would just set a "default" address to 0x27/0x3f if the pins happened to beunconnected.
Quote from: bperrybap on Apr 26, 2013, 04:48 amAre you saying that the A0, A1, A2 pins on the 8574 are not connectedto anything? Did you ohm it out?A0, A1 and A2 has contact but only to GND. But you need contact to VSS too to change the address. A0, A1 and A2 has contact to GND that means that they use address 0x20 or 0x27. Don't know which kind of chip they use.Micky