is the Atmel ISP Programmer harmfull ?

[toyib]

atmel isp programmer

https://wiredworld.tripod.com/tronics/atmel_isp.html

in the circuit we can see there are 4 pin that connected
2 >> 12 connected
3 >> 11 connected
is it not harmfull for our computer (pararel port)?



thank's

 

[nandhu015]

No it wont

This circuit is working well for years

Regards
Nandhu

 

[toyib]

ok....
but im affraid to try it.
anyone else that have use this circuit

which is the best when we use 74LS245 and 74LS244?

thank's

 

[FvM]

Why do you think that connecting a data output to a status input should cause any problems? Funny question.

 

[toyib]

i think its harmfull when 1 pin is hight an other is low.
it will harmfull for our pararel port
cause im don't understand too the port,

which is the best when we use 74LS245 and 74LS244?


ok guys thank's for answer

 

[xxtigerxx]

if you are afriad use reistor in series like 1kohm from mcu to pc.

 

[FvM]

i think its harmfull when 1 pin is hight an other is low

Yes, if you are connecting two outputs. This isn't the case here.

cause im don't understand too the port

There are plenty of internet resources that discuss LPT details. E.g.: **broken link removed**

if you are afriad use reistor in series like 1kohm from mcu to pc.

This probably doesn't work when sending data to LPT status inputs. They may have a strong pull-up resistor, so you won't achieve a realiable low level. 100 ohm would be more suitable.