Lutetium
even QSPI isn't close to frame buf territory
you can use it for audio I guess and some background data
my application is non-video so the speed wasn't a huge concern. Fastest communication was WiFi / CAN
can the spi be overclocked, or bitbanged faster with i2s?
having the RAM was a godspeed
I think for my application I'm going to have to sit down with the scope.
@bitluni if you wanted to try and bitbang SDI to a sdi to hdmi chip for HD I would look at TI's datasheets for their serialzer/deserializer SDI chips.
I hadn't thought to use the I2S for what I was doing but now see how it can be used to DMA data out really fast.
what is the actually bottlenck with PSRAM? my understanding was PSRAM itself is simply slow, or is it in fact SPI?
I had looked harder at MCPWM
have a feeling that I'm going to need to just try to make some waveforms and have scope hooked up.
@andrew.michael.johnson thanks :-) another neat clue on the quest for HDMI for the esp32
http://www.ti.com/product/LMH0041 LCD screen anyone? lol
You get SDI working and things open up quite a BIT
lol
@morgan, it's quad-SPI. bottleneck = SPI bus speed, bus width, protocol overhead. You can get many Mb/second but not anywhere near Gb/sec. I didn't benchmark it because I didn't need the speed. Also, I think it may share the bus with the QSPI dataflash for program memory
ok, good to know
So we're well over an hour now and going strong. I don't want to end the fun, but bitluni has been very generous with his time and expertise, and he may need to get back to real life. If so, I just want to say thanks for coming along, this was great!
yeah! thank @bitluni
SDI-3G (3gbs) is the base standard for SDI but lower resolutions I believe can be achieved at lower speeds.. The issue is SDI is generally uncompressed video. I think it can be compress but I am not entirely sure.
thanks....
And I just want to drop a pitch for next week's Hack Chat, Python and the IoT with the Adafruit CircutPython team:https://hackaday.io/event/164062-python-and-the-internet-of-things-hack-chat
I check the math back then when I was implementing camera support. psram it was not fast enough for qvga. It would work if you buffered half the frame in sram and the other half in the psram :-D
Really interesting @bitluni , Regards to @Dan Maloney and everybody.
pt, LadayAda, and a whole bunch of other devs and folks from the CircuitPythn team will be here, plus we'll be doing a giveaway...
thanks @bitluni!
it went quite low level
yw
Appreciate the novel idea for I2S abuse.
:)
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