I spent four weeks looking for one. So not that I know of or I would have
used it. These guys were the only ones that would take it as far as they
did. Everyone else wants and NDA to get what I got form NXP without one..
Gerald
On Fri, Jan 23, 2015 at 11:27 AM, wojtekskulski via BeagleBoard
Gerald:
thank you. Just a small point. According to
TDA19988-product-datasheet-rev3-jul2011.pdf, only some inputs on TDA19988
are 5V-tolerant. The ones connected to the AM335x are not. These are listed
on page 38, table 30 as Not 5 V tolerant CMOS 1.8 V and CMOS 3.3 V
tolerant. I wanted to
Well, it works. Remember, these signals are 3.3V and the threshold on the
HDMI chip is for a 1.8V rail.
Feel free to try the series resistors if you like.
Gerald
On Wed, Jan 21, 2015 at 3:58 PM, wojtekskulski via BeagleBoard
beagleboard@googlegroups.com wrote:
Gerald:
thank you for the
Gerald:
thank you for the answer. I am a bit surprised that caps on the LCD_DATAx
are helpful. My understanding is that they must slow down the edges because
the AM335x drivers are forced to charge them, what just takes time at a
given AM335x buffer strength, 6 mA in this case (data sheet
Too many loads on the signal. The HDMI encoder is a 1.8V input that is 5V
tolerent. So we had to add the filters to make the output of the HDMI work.
Serial resistors did not work. We tried that first. Remember you have the
HDMI device, the boot resistors, and the LCD load to contend with.
Gerald:
what was the issue that you solved with 47 pF caps on page 10 of the BBB
schematics? I am guessing you wanted to slow down the edges. Why and by how
much? Was it a serious problem or a sort of optimization?
I am tempted to replace these caps with serial resistors to save some
power.
