Has anyone any experience with using the ATTiny85 with Dallas 1-wire interface? I am trying to design a circuit for messing around with writing AVR-C programs for controlling TI-5973 LED Drivers. The TI-5973 uses 1-wire interface. I found a datasheet on Microchip's site that details using 1-wire by software or with a UART TXD Buffer circuit. Given the limited memory space in the 85, I figured that the latter was better. I have sketched out a circuit design that I think will work, but I'd love to get some feedback. I still need to add the capacitors for the power source and the XTAL oscillator crystal (for which I still haven't figured out if it should be 16 or 20MHz), but this is mostly the basic concept.
What makes you think that the TI-5973 uses an interface in any way similar to a Dallas one-wire?
What is a "UART TXD Buffer circuit" and why would it be relevant to driving TI-5973s or in any way be relevant to the amount of memory space on the ATTiny85?
Paul__B:
What makes you think that the TI-5973 uses an interface in any way similar to a Dallas one-wire?
The section in the datasheet that reads "The device adopts a single-wire input or output system. Therefore, communication wire cost and communication wire failure are reduced. Further wire cost reduction can be attained when supplying power to the device."
Paul__B:
What is a "UART TXD Buffer circuit" and why would it be relevant to driving TI-5973s or in any way be relevant to the amount of memory space on the ATTiny85?
That is the circuit as described in "Atmel AVR318: Dallas 1-Wire Master on tinyAVR and megaAVR" for preforming 1-wire signaling using UART. I just figured it would save programming space to not have to include the software variables. If it's a situation of "six one way, half a dozen the other" please tell me so I can remove the buffer.
I think the point that Paul__B is trying to make is that just because the uses a single wire for communication, doesn't mean it uses the Dallas 1-Wire protocol. If you look in the TI-5973 datasheet it gives details of the communication format which is quite different from 1-Wire.
Ah, I wish he had simply said that. I guess I was over thinking it; that makes things much more simple. So I should just directly connect the 85 to the 5973's? I can't seem to find any info on if the last SDO should be left unconnected or if it should go to ground. What's best practice here?
Also, any tips on the XTAL oscillator speed? The 5973's internal GS clock is 12MHz; I don't know if that makes a difference in what MHz crystal to use for the 85.
