[TI-H] help with hardware
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[TI-H] help with hardware
Hi! My first post to this mailing list. The sketch below shows an early pla=
n for a four-way communication adapter. I don't feel like going through h=
ow it's supposed to work. But I'm looking for potential dangers to the ca=
lculators. As you can see (or maybe not =3D) the calcutors share ground w=
ith the 4.5V battery, could that damage them? Also there are no resistors=
in this circuit, except the internal resistance in the IC:s. I've heard =
it's quite easy to burn the link-port of the calcs. Anyway, i'm sorry for=
this messy circuit plan (use fixed width font). Anyway, if there are any=
(to you) obvious faults to this sketch, i'd be glad if you tell me befor=
e i build it and waste four expensive calculators =3D)
GND
__________ | _____________
_| " |__ | |___|_ |
_| 7 |__|_|_|___| |_|_|_|_|_|_|_|
__| 4 |__|_|_| | 74153 |
| _| 9 |__|_|_|___ |_____________|
| _| 3 |_ | | | | | | | | | | | |
| _|___|__| | | |_|_|_|_|_|_| |
|___________|_|_____|_|_|_|_|_____|
| | | ___| | | | |
+ | | | |D|___| | | |
4.5 | | |A|___|_| | |
- | | | |4|___|_|_| |
|___|_| |1|___|_|_|_|
| | |4|_ | | | |
| | |8|_ | | | |
| | |A|_ | | | |
| | |_|_ | | | |
_|_|_______| | | |
| | | ______| | |_____
| |_|__|________|_______|_
| | |__|_|______|_|_____|_|_
| | | | | | | | | | | |
D D G D D G D D G D D G
0 1 N 0 1 N 0 1 N 0 1 N
D D D D
CALC0 CALC1 CALC2 CALC3
Regards
David Revelj