Quad State Address Pins
DigitalDj
Posts: 207
Hello!
Can someone explain Quad State Address pins?·
This is on a chip that it's buss is I2C!
How do·you address this type of chip or multiple chips, what would be the wiring configuration?
Thanks,
Kevin
·
Can someone explain Quad State Address pins?·
This is on a chip that it's buss is I2C!
How do·you address this type of chip or multiple chips, what would be the wiring configuration?
Thanks,
Kevin
·
Comments
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Jon Williams
Applications Engineer, Parallax
It is the Max7313, here is the doc page. I also included a sample of the circuit!
http://pdfserv.maxim-ic.com/en/ds/MAX7313.pdf
I am wanting to learn how this works and how to hook up multiple chips and how the addressing works as far as wiring and programming. This circuit uses a different processor and i am wanting to use a SX.
Kevin
Post Edited (DigitalDj) : 8/24/2005 3:04:08 AM GMT
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Jon Williams
Applications Engineer, Parallax
·· That's actually considered a 4th state?· I'd think PWM would fall under output HIGH & output LOW.· Interesting indeed.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
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Greetings from Germany,
Günther
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Jon Williams
Applications Engineer, Parallax
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·
Steve
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
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Jon Williams
Applications Engineer, Parallax
·· Even with Guenther's explanation I still don't see 4 states, but okay.·
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Chris Savage
Parallax Tech Support
csavage@parallax.com
I agree with you, "state" usually means something "static", so a pin level could be V+, ground, or Hi-Z, i.e. three states. In most cases, this is used with outputs, although I also saw devices, like PLL clock chips, with Tri-State inputs used to select the clock frequency.
Actually, I did not use "4-State" in my post, and I did not find it in the MAX7300 datasheet either. Maybe, a term like "4-mode input" better describes how these inputs work. MAXIM must have integrated some tricky logic to determine if such pins are tied to V+, Ground, or if the pin levels either follow the SCL or SDA level changes.
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Greetings from Germany,
G
·· Thanks for clarifying.· When I start thinking there are new "states" that I never knew about it reminded me of how far behind I am in what I should know compared with my years of experience.·
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Chris Savage
Parallax Tech Support
csavage@parallax.com
I'll tell you a secret - I hope nobody else will read that post though
IMO, we engineers are always behind a great deal of knowledge, as even 24 hours per day would not be enough for an individual to accumulate all the latest technologies and developments. Fortunately, we all do have different strengths and weaknesses in knowledge and experience (did I ever use Laplace transformation since I graduated, or did I ever use a Smith diagram since then?).
What makes it so exciting being an engineer today is the ease of gathering information via the Internet, right when you need it, and the ease and speed of exchanging experiences with others all over the world via forums like this.
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Greetings from Germany,
Günther
·· As always thanks for your wisdom and insightfulness.·
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Chris Savage
Parallax Tech Support
csavage@parallax.com
How can i make these chips·work for me using a SX processor. I guess the main question is how to understand the addressing by configuration and programming.
Oh by the way! the diagram is a partial diagram of a circuit that some students at MIT designed and built. Bean i think told me about this website. They have also programmed the circuit for sound to light control.
http://web.mit.edu/storborg/ddf/index.html·Check it out! Very impressive!
It has just been real hard to communicate with these guys and i am trying to get some circuit ideas worked out before winter to do a schematic make circuit boards etc.
I am also looking at multiplexing the led's for simpler wiring. Here is a color cube that i designed that is now connected to a sound to light controller like from the 70's that i changed to drive the led's. With using the led's the response is so much quicker and the color mixing·from sound is real color creative.
Is there some books that anyone can suggest that i can get to help me with understanding up to date processors and digital electronics.
Leave it to me to pick your brains and spark understanding of new technology!
Kevin
Thanks,
Kevin
·
·· Sorry the topic got "off-topic" there...I don't know anything about that chip.· Anybody else?
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Chris Savage
Parallax Tech Support
csavage@parallax.com
the address lines available on almost all I²C devices are used to statically assign a unique address (or device-ID) to each device that is connected to the bus. When you want to "talk" to an I²C device, you first will have to generate a so-called "Start condition", i.e. the SDA line goes low while the SCL line stays high. Next, the device-ID byte is sent via the bus. Normally, the device-ID byte is composed of three parts, some fixed bits "hard-coded" by the device manufacturer in the highest bit positions, followed by some more bits where the number of these bits depends on the device's available number of address select pins, finally followed by the last bit that is used to indicate a write (bit = 0), or read (bit = 1) operation.
IOW, the upper 7 bits in the device-ID byte are used to select a specific device on the bus, and all devices attached to one bus must be configured to have different, i.e. unique device-IDs.
The MAX7313 series of I²C components is a bit special, compared to other devices. They come with three address select pins (AD2...0) where each of these pins may be tied to GND, V+, SCL, or SDA level. Most other devices only allow to connect the address select pins to V+ or GND, so with three pins you could compose eight different IDs (000...111). As each of these three pins can have two more "states" on the MAX7313 devices, this means you can compose 64 different IDs. Thus, the MAX7313 devices don't have a "hard-coded" address part at all - the device-ID is under your full control.
Let's assume, you are going to just connect one MAX7313 to the bus. In this case, you might hard-wire all three address pins to GND level. According to table 1 in the MAX7313 datasheet, this results in an ID of 0100000x (where "x" is the read/write bit). When you plan to connect another MAX7313 to the bus, you would hard-wire the A2 and A1 pins to GND, and A0 to V+. According to the datasheet, this assigns the ID 0100001x to the second device.
I recommend, carefully studying the MAX7313 datasheet, and maybe some general documents about the I²C bus, and the I²C protocol. Via Google, you should easily find the I²C specs published by Philips. They pretty well explain the I²C secrets.
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Greetings from Germany,
Günther