When would one use the 876 instead of the 877?

It seems that the 877 offers a lot more io and memory for a few cents more.

 

For a smaller board.. I guest

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Falleaf
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Other companies would... For mass production they try to save every penny they can.

The few cents you say turn into big numbers when you're mass producing something.

 

I think you have the question the wrong way round :lol:

It should be 'when would one use an 877 instead of an 876', the answer is when you need more I/O than an 876 provides.

You don't get more memory, just more I/O, they are pretty well identical chips - but one has less legs :lol:

The biggest advantage of the 876 is the 'skinny DIP' case, it makes it a lot smaller - the 877 is just huge! - if the 876 was full width, it wouldn't be half as useful.

If you use an 877 where an 876 would do, you are obviously wasting some facilities on the chip - money wise, there's not any difference worth bothering about. I use both, if an 876 will do, I'll use that - if it won't, I move to an 877 - if I was starting a project, where I suspected I might need as much I/O as possible, I'd probably start with the 877 to begin with.

 

The 877 is available in PLCC package. Wich is quite small, There are sockets for these smd packages, that convert the pins to normal spacing so you can use them on normal boards

ever seen a 877 in TQFP package. smaller then a F84

 

I've not seen one, but I usually ignore other than DIL chips, as I don't do PCB's - but I've seen plenty of tiny SM chips, a 40 pin one can be really small.

 

Previously, i use 877 in my project. However, while i plotting the PCB layout, i realise 877 is waste of space. (of course, i am using the DIP). As there are many unused pins in my 877, i replace it with 876 and just made some slight change in my program.

Why microchip produce such wide range variety of microcontroller??
cost is a factor. 877 is more expensive, and making the cost of PCB higher.
so, if you dont need so much pins, why would u wan to use 877.