| Electronics > Beginners |
| LED indicator for data pin |
| (1/2) > >> |
| Lucky-Luka:
Hi all I would like to understand the connections that allow leds to blink as Tx and Rx are working in a serial communication. In the video I show what I mean. I have a connection between a FPGA and a breadbord with a PIC. I want to include in my pic board the little board with the max3232 so I was wondering how to connect leds to show when some data is flowing. Are they in parallel with data lines? In such a way don't they change signal levels? Cheers https://youtu.be/kKMO86WT7o4 |
| Rerouter:
In general they are in parrellel with the data lines, as most TTL signalling is active low, they have a pullup from positive to limit there current to 0.5-2mA, and when the RX or TX goes to ground they light up. |
| Lucky-Luka:
Hi so, if I've correctly understood, I should do something like the attached image (image found on internet). Am I right? Cheers |
| Rerouter:
You want the top half of the image, not the lower half |
| Lucky-Luka:
With the top half part of the image don'tI change the level of the pin input? btw which R value should I use? Cheers |
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