« previous topic   next topic »
Pages: [1]   Go Down
Author Topic: How to connect LEDs to RX0/TX1 and still be able to flash?  (Read 470 times)
0 Members and 1 Guest are viewing this topic.
acid
Offline Offline
Newbie
*
Karma: 0
Posts: 48
View Profile
« on: November 30, 2012, 03:07:02 pm »
 Bigger Bigger Smaller Smaller Reset Reset
I've tried to connect 2 leds on Digital Pin0 and Digital Pin1. I know it's connected to UART RX/TX. After this connection I wasn't able to flash device - no response.
But there must be some way to isolate this LEDs from RX/TX pins during programming(except putting release buttons).

So I want to have LEDs on those pins (using all pins on Arduino UNO) and be able to program board.
Logged

Boffin1
Cape Town South Africa
Offline Offline
Edison Member
*
Karma: 18
Posts: 1139
A newbie with loads of posts, and still so much to learn !
View Profile
WWW
« Reply #1 on: November 30, 2012, 03:19:57 pm »
 Bigger Bigger Smaller Smaller Reset Reset
What have you got connected to all the other pins ?   more leds?
Logged
We live in the era of the smart phones and stupid people.

Grumpy_Mike
Manchester (England England)
Offline Offline
Brattain Member
*****
Karma: 437
Posts: 28691
Solder is electric glue
View Profile
WWW
« Reply #2 on: November 30, 2012, 03:20:19 pm »
 Bigger Bigger Smaller Smaller Reset Reset
The best way is to switch them out. That is physically disconnect them.

Alternatively you can use a buffer or a transistor to isolate them from the serial signals. They will then flash as you upload stuff but when the sketch starts running they will be fully controllable.
Logged

acid
Offline Offline
Newbie
*
Karma: 0
Posts: 48
View Profile
« Reply #3 on: November 30, 2012, 03:21:17 pm »
 Bigger Bigger Smaller Smaller Reset Reset
Other LEDs, SPI. The number of pins are exactly matches to requirements if I only can isolate them and use flash device without disconnecting LEDs.
Logged

acid
Offline Offline
Newbie
*
Karma: 0
Posts: 48
View Profile
« Reply #4 on: November 30, 2012, 03:22:26 pm »
 Bigger Bigger Smaller Smaller Reset Reset
Quote from: acid on November 30, 2012, 03:21:17 pm
Other LEDs, SPI. The number of pins are exactly matches to requirements if I only can isolate them and use flash device without disconnecting LEDs.

Could you please give me some reference values of elements?
Logged

Boffin1
Cape Town South Africa
Offline Offline
Edison Member
*
Karma: 18
Posts: 1139
A newbie with loads of posts, and still so much to learn !
View Profile
WWW
« Reply #5 on: November 30, 2012, 03:39:37 pm »
 Bigger Bigger Smaller Smaller Reset Reset
You can drive loads of LEDs from 3 pins with a shift register ....
Logged
We live in the era of the smart phones and stupid people.

Grumpy_Mike
Manchester (England England)
Offline Offline
Brattain Member
*****
Karma: 437
Posts: 28691
Solder is electric glue
View Profile
WWW
« Reply #6 on: November 30, 2012, 06:12:34 pm »
 Bigger Bigger Smaller Smaller Reset Reset
Quote from: acid on November 30, 2012, 03:21:17 pm
Other LEDs, SPI. The number of pins are exactly matches to requirements if I only can isolate them and use flash device without disconnecting LEDs.

You can't without isolating the LEDs from the serial input. As I said before you fdo this either electrically or mechanically.
Logged

Pages: [1]   Go Up
« previous topic   next topic »
Jump to: