Added doc for ws2812b_phy

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Markus Koch 2016-11-05 15:10:25 +01:00
parent bb76c45367
commit 6e5249641d
1 changed files with 40 additions and 2 deletions

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@ -13,7 +13,45 @@ For directories containing VHDL source files, the directory name denotes the VHD
### ws2812b_phy
Low level driver for the WorldSemi WS2812B RGB LEDs. Handles bit timing and command separation.
*Documentation coming soon*
<pre>
+ +
| |
| |
+-----------+ +----------------------v----v------+
| +----> pixData_red[7:0] clk rst |
| | | |
| +----> pixData_green[7:0] |
| | | | +----+
| User +----> pixData_blue[7:0] so +---->LEDs|
| Logic | | | +----+
| | | |
| +----> pixData_valid |
| | | |
| <----+ pixData_next |
+-----------+ +----------------------------------+
_ _ _ _ _ _ _ _ _ _ _ _ _ _
clk _/ \_/ \_/ \_/ \_/ \_/ \_ / / \_/ \_/ \_/ \_ / / \_/ \_/ \_/ \_
_______ _______ / / _______ / /
data ---------<_______X_______ | | _______>------- | | ----------------
_______________ \ \ _______ \ \
valid _________/ \ \ \_______ \ \ ________________
___ | | ___ | | ___
next _____________/ \_______ / / ___/ \_______ / / ____/ \_______
/ / / /
1 2 3 4 5 6
1: User applies first LED's data and asserts pixData_valid.
2: PHY acknowledges that it latched the data and starts supplying the
information to the LED string.
3: User logic sees the pixData_next strobe and prepares the next data.
4: Next data is latched. Steps 3 and 4 are to be repeated until each LED in
the string has been given a value.
5: User logic sees the pixData_next strobe. As all LEDs have already been
given a value, pixData_valid is deasserted to signal the end of a string.
6: The completion of the reset time is signalled using another
pixData_next strobe.
</pre>
For an example, see Rainbow.