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padi performance
#1
hello,

Using spi interface (perhaps with overclocking) what kind of data throughput can be achieved?
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#2
(01-29-2017, 09:35 PM)ktc Wrote: hello,

Using spi interface (perhaps with overclocking) what kind of data throughput can be achieved?

up to 41.5Mhz
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#3
200*5/6/4 MHz =41.666MHz is the maximum when you "overclock" PADI (RTL8710) to 200*5/6 = 166.666Mhz CPU clock. Default is 83.333MHz, as it's setup.

As long as you are able to feed the data on-time, it will produce a perfectly continuos stream at that frequency/ bit rate.

If I remember correctly, you can got a few (x) milis/micro seconds to feed DMA another page. If your program does not make on the time, the SSI's peripheral's clock will stop, and it will take a few (y) mili/micro seconds to restart.

See, my VGA generarating code ( http://www.github.com/kissste ), or any other SSI example included in the SDK or RTLDuino,, tweak parameters and test.

I'm sure, there must be a way to push even more by playing with PLL registers and etc.
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#4
PVVX has managed to overclock to 200MHz by setting a register that eliminates that 5/6 multiplier.

Based on his testing, everything appears to be working. There is a bug in SDK's code (u32 overflow) that sets a divisor for UART, once patched UART is fine too.

SSI/SPI will now run @ 200MHZ/ 4 = 50MHz since it's derived from the same clock.
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