Help:should the ATN (pin#3) on BS2 be grounded

Archiver

(1) Should the ATN pin be grounded through a capacitor 0.01uF? or is it ok to
leave it alone, not connected if not used? why? thanks.
(2) whats the best way to connect a pushbutton? 220 resistor grounded to a 1K?
thanks again.

---

Do you Yahoo!?
SBC Yahoo! DSL - Now only $29.95 per month!

[noparse][[/noparse]Non-text portions of this message have been removed]

Archiver

> (1) Should the ATN pin be grounded through a capacitor 0.01uF? or
is it ok to leave it alone, not connected if not used? why? thanks.
> (2) whats the best way to connect a pushbutton? 220 resistor
grounded to a 1K? thanks again.

Hi

In fact in many cases it is ok to leave ATN floating. However, the
best solution is to ground it via a 100nF (= 0.1uF) capacitor and
maybe a 3k3 resistor in parallel. Also connect the DTR line from the
serial port throug another 100nF capacitor:

100n
DTR---||----+---+---- ATN
_|_ |
100n --- /
| \3k3
| /
_|_ _|_

To make a reset push button connect the RST pin through the button
contact and through an 1k resistor to ground (the resistor is
optional). The ATN is internally tied to the RST via a transistor.
Pulsing ATN high pulls RST low and causes the reset.

Regards
Adrian