21 lines
738 B
Plaintext
21 lines
738 B
Plaintext
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See the top level README for information on where to find the
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schematic and programmers reference manual for the ARM processor
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on the raspberry pi.
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Based on some web searches the gpio is based at address 0x20200000 not
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0x7E200000 as shown in the documentation. I have to go figure that out.
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There is a free-running 64 bit timer, super easy to use, just read it.
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Based on a couple of experiments, without messing with anything it
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appears that the timer is runing at about a megahertz, 1 million ticks
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per second. I am guessing it is divided down from the 700MHz somewhere,
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will dig deeper.
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Hmm, there are comments in the manual about the system clock coming up
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at 250MHz. I wonder if this system timer is 250MHz/256 = 0.976MHz.
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