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Topic: MAX485 chip different pin outs (Read 1 time) previous topic - next topic

jeffez

Nov 29, 2016, 08:02 am Last Edit: Nov 29, 2016, 09:32 am by jeffez
Hey guys,
I'm a bit confused as there appears to be two (or more??) standards for which pins are for what on max485 chips. This picture shows the two and it looks like i have bought a set of one type (maxim branded) and expected it to be the other. What soft of brand/make of chips do i need to get the standard pin out on the top left.

Thanks


ElCaron

#1
Nov 29, 2016, 09:38 am Last Edit: Nov 29, 2016, 09:41 am by ElCaron
I don't understand your question. The MAX485 is a chip from Maxim. If it is from another brand, it is not a MAX485. Something like the ST485B might be compatible (didn't check), but it is not a MAX485.
Maxim sells it in at least three packages: DIP, SO and µMAX. The latter is a proprietary format that is specific to to Maxim: http://electronics.stackexchange.com/questions/15839/what-is-%C2%B5max-ic-package

If you buy the chip as DIP or SO, you get the top layout, if you buy it in µMAX, you get the bottom layout.

jeffez

I don't understand your question. The MAX485 is a chip from Maxim. If it is from another brand, it is not a MAX485. Something like the ST485B might be compatible (didn't check), but it is not a MAX485.
Maxim sells it in at least three packages: DIP, SO and µMAX. The latter is a proprietary format that is specific to to Maxim: http://electronics.stackexchange.com/questions/15839/what-is-%C2%B5max-ic-package

If you buy the chip as DIP or SO, you get the top layout, if you buy it in µMAX, you get the bottom layout.
All of the maxim chips i have seen selling online have something like cpaXXXX on them. The ones i have are cpa 528. I will have to just assume then that if its the maxim proprietary layout, it would clearly say so with µMAX. So from your answer i was able to work out my chips are DIP by looking back at the store listing where i got them.

I have spent all day trying to get two max chips to talk to each other. If my circuit is correct it must be a software issue.

sterretje

uMAX versions are marked MAX485CUA; see the datasheet ( ;) )
If you understand an example, use it.
If you don't understand an example, don't use it.

Electronics engineer by trade, software engineer by profession. Trying to get back into electronics after 15 years absence.

ElCaron

#4
Nov 29, 2016, 01:06 pm Last Edit: Nov 29, 2016, 01:07 pm by ElCaron
i was able to work out my chips are DIP by looking back at the store listing where i got them.
That makes no sense. You only have to look at the chip.
Does it look like this:
1. DIP8
or like this:
2. SO8
or like this:
3. µMAX?
Note that 2. and 3. look similar on first glance, but they are different. E.g., the legs are much closer in 3.

If you chips are DIP, you have to stick them through your PCB to mount them (or in a socket). 2. and 3. are surface mount.

Riva

I have spent all day trying to get two max chips to talk to each other. If my circuit is correct it must be a software issue.
Can you post your circuit so we can see how you have connected the chips and if your controlling the ~RE/DE from the Arduino (instead of tying to VCC/GND) maybe also post your code.
Don't PM me for help as I will ignore it.

jeffez

#6
Nov 29, 2016, 01:54 pm Last Edit: Nov 30, 2016, 01:01 am by jeffez
That makes no sense. You only have to look at the chip.
Does it look like this:
1. DIP8
or like this:
2. SO8
or like this:
3. µMAX?
Note that 2. and 3. look similar on first glance, but they are different. E.g., the legs are much closer in 3.

If you chips are DIP, you have to stick them through your PCB to mount them (or in a socket). 2. and 3. are surface mount.
Ah ok that was my ignorance. I didn't know theere were words for types of chips and thought that it would be written on it. I have the through hole ones so yep DIP8.

Can you post your circuit so we can see how you have connected the chips and if your controlling the ~RE/DE from the Arduino (instead of tying to VCC/GND) maybe also post your code.
My intention was to, i was tearing my hair out for a whole day. The volume of code in the project is a bit much across multiple files so i made a test demo to post but then it worked. I was able to send single bytes between two max chips. So looks like there's something missing/broken ill have to find in the project.

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