Contacting/packaging is the major part of the manufacturers' expenses per IC. Moreover, I/O circuits and contact pads form often a significant part of the chip's area. Market can deform the expense/cost ratio of course; but the overall tendency remains. If your distributor quotes AT89C4051 by 40% more than AT89S51, then you can surely find an another supplier for AT89C4051 (or they are rarely used in your area). They go for around $1.71 vs. $1.87 (excl.VAT) for S52 for a single piece, no discount, at a popular online-shop here - not the cheapest option (btw. they have mega8 for $2.67).


Rapid prototyping on protoboards. Design on low-cost=cheaper boards with relatively wide tracks and spaces. Manufacturing cost, when in-house cheap through-hole facilities exist. Programming/handling/field repair (drop-in chip replacement).

Shall I write it over and over again? Case dependent. Country dependent. Time dependent. Circumstances dependent. For example, decision factors I am mentioning are Slovakia, early 2005, small starting company, mcu needed for the "little boy" task, IAP required, learning curves very steep (highly motivated, educated young people), cost is an absolute priority - your may be completely different.


Why on Earth not? If it is cheaper, then yes. And it may be cheaper, depending on circumstances.


Yes we do. Remember, the little boy not the fat man. I don't like comparing apples and pears (or even carrots and chocolate).

Jan Waclawek