correct measuremant

This commit is contained in:
King Kévin 2015-07-17 10:01:14 +02:00
parent 31a56136e1
commit c2678063c8
1 changed files with 7 additions and 2 deletions

9
README
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@ -35,6 +35,7 @@ Use `make` to compile and flash it.
VLC will send the coloer values over USB, going to the serial UART.
`lib/ws2812b` allow to control WS2812B LED strips.
The data transmission is done implemented in assembly since it is time critical
The LED strips are connected in parallel as follows:
- 11 LEDs on pin D2 (PD2) for the top first LED strip
- 08 LEDs on pin D3 (PD3) for the top second LED strip
@ -75,9 +76,13 @@ A example for a white picture is available in `vlc-fnordlicht-dump.txt`
limitation
==========
Don't forget to short the reset pin of the microcontroller with 5V to prevent reset when the serial port is open.
Else the firmware will miss the start of VLC's communication (the sync) while booting.
This would make the LED light output garbage.
In the current WS2812B implementation setting an LED colors requires 36 us.
Outputting the data to the WS2812B strips requires 38 us for a single LED on all pins/strips in parallel.
For 11 LEDs per strip is requires 368 us.
Outputting the data to the WS2812B strips requires 48 us for a single LED on all pins/strips in parallel.
For 11 LEDs per strip is requires 348 us.
The fnordlicht protocol uses a baud rate of 19200 bps with 8N1 configuration.
Thus sending/receiving one byte requires 1.0s/(19200bps/(8+1)bits)= 469 us.