<petrosky>
that the interrupts needs to check on polling way
<petrosky>
is it true?
<zmatt>
petrosky: yes, PRUSS has an interrupt controller to latch and prioritize events, and two of its outputs are routed to bits 30-31 of r31 of both pru cores
<zmatt>
a PRU program is normally dedicated to some particular (often timing-sensitive) task so having actual cpu interrupts is generally neither needed nor even desired due to the timing unpredictability they would introduce
<zmatt>
note that since the interrupt lines are wired into register, they can be directly tested using a conditional branch
<zmatt>
so polling for an interrupt takes only a single cycle per poll
<petrosky>
zmatt for your explanation
<zmatt>
(the PRUSS interrupt controller also has outputs to the Cortex-A8 interrupt controller)
<mattb0ne>
zmatt
<zmatt>
petrosky: it's also possible to enter the PRU core into a sleep state from which it will be woken up by bits in r31 being set (with a configurable mask), hence in particular this can be used for a power-saving wait-for-interrupt
<zmatt>
mattb0ne: not sure what you mean, it looks like all power supplies are available on the terminal blocks, both the outputs (sys_5v, vdd_3v3b) and the input (vdd_5v)
<zmatt>
what's a bigger problem is that this thing connects terminals to the eMMC pins, which is a great way to risk eMMC communication errors
<zmatt>
(unless eMMC is not used)
<mattb0ne>
so if I want to put 5VDC into the board I use the VDD port
<mattb0ne>
5V vdd port
<zmatt>
vdd_5v (P9.05/06) directly connects to the center pin of the 5V barrel jack
<zmatt>
so feeding power into that is completely equivalent to feeding power into that jack
<mattb0ne>
ok and what about return wire do I care.
<mattb0ne>
like to make a loop
<zmatt>
ground? :P there's a ground pin right next to it
<zmatt>
ground terminal I mean, on the block
<zmatt>
and needless to say, since vdd_5v connects directly to the barrel jack, you should not attempt to feed power into both of them at the same time
<mattb0ne>
ok
<zmatt>
since that would likely cause one supply to backfeed into the other
<mattb0ne>
so v+ into vdd_5v and v- into ground
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<mattb0ne>
I have a conceptual question regarding powering the beagle by the vdd_5V rail
<mattb0ne>
I am only going to connect one wire from the a step down transformer to the rail and nothing else
<mattb0ne>
where I am confused is how is the current loop completed or is the beagle doing something to make it a complete circuit
<zmatt>
how come you understood how to connect it two hours ago but suddenly no longer do?
<zmatt>
22:47 < mattb0ne> so v+ into vdd_5v and v- into ground
<mattb0ne>
sometimes facts fall out of my head
<mattb0ne>
lol
<mattb0ne>
i thought I did then I pondered than i didnt
<mattb0ne>
i guess the connetion to GND is what throws me off
<zmatt>
in general, everything needs to share ground (this isn't technically always true, but it's close enough to being always true that it's an easy rule)
<zmatt>
sharing a common ground is what allows different parts of a circuit to agree on voltages, e.g. your supply output produces 5V relative to its ground, the beaglebone supply input needs 5V relative to its ground... until you connect those grounds together, your supply has no meaningful output voltage from the beaglebone's pov
<zmatt>
a common ground is what allows everything to agree on what 5V means