I've seen a few posts recently where dubious reset circuits have been used and may or have caused problems.

I was always a fan of the DS1813, but they seem to have gotten relatively pricey so I tried some other circuits based on the 2N7000, but although it worked it really was out of spec. for the 6502. A few months ago I came up with he following based on the MCP100. I use the "H" variant with a threshold voltage of 4.475V and it works flawlessly. The added bonus is that it's 1/6 the price of the DS1813 going for less than $0.50 from DigiKey.

The resistor values are not critical as long as the supply is drawn down below the threshold voltage.

It provides power-on, push-button and brown-out reset of about 350ms or more. Effective, simple and cheap, who could ask for anything more?



Update: Added some screen shots. Green trace is Vcc, yellow is /Reset. (sorry, the green trace was not set to 10x)

Power-on reset





Brown-out reset





Push-button reset

_________________
Bill

Yep, mcp130-450di/to is the part I use for every design. I buy it 100 pcs at a time because I use it so much.
Bill
Edit, OK, I didn’t buy 100pcs last time; it was 200pcs.

Not me! Thanks, that's really useful

I've still got a few DS1813s left but at 5 to 10 times* the price of the MCP100 it means I have to really stop and think before using one.

* Here in SA. Variance depending on local stock, the Rand exchange, import / postage and the phase of the moon.

MIC708MY looks a good choice too, if you can cope with SOIC-8 surface mount parts (and when I last bought, Mouser had them in stock but none of the MCP parts). At much the same price.

Neil

Bill (plasmo) got me hooked on the MCP130, very similar to your MCP100. I also add the pull-up resistor like you, but not the pull-down resistor.

I concur that the DS1813 is much more expensive than this alternative. Looks great

Chad