PASM Reset

ke4pjw

I have been using

clkset  (255)

to reset the Prop from PASM. I have found that this is not always reliable. I am unsure if possibly the clock frequency is not reset once the prop is reset or if there is other magic causing me grief. (Such as my other hardware needs a reset)

Thoughts?

Peter Jakacki

Why are you setting all the clock field bits?. Just write $80 otherwise you are trying to enable other settings.

ke4pjw

I couldn't determine from the Prop Manual what the bitwise operation was against the current settings. I figured if I was resetting, it wouldn't matter. Obviously it does. I will try 128. Thanks!

Electrodude

Also, you don't need the parentheses. It's an assembly instruction, not a Spin function. Also, it's probably more clear if you use a hex or binary constant, since it's a bitfield and not a decimal number.

clkset $80

EDIT: This is wrong. You can't specify an immediate value in an instruction's destination field. See PhiPi's post below.

ke4pjw

I don't recall why I used the parens. IIRC, it was in an example I found out on the net.

I received a PM that clkset uses indirect addressing, therefore it is looking at the values in the register address you are pointing at.

I don't know if the parens allow you to pass a literal value. Could be some compiler trickery.

Either way, I will fiddle with it and determine if a literal value can be passed and if not, I will fix my code.

Thanks guys!

--Terry

Phil Pilgrim (PhiPi)

You can't write an immediate value to the clock register, since the argument is the D field of the instruction, not the S field. So you will have to define a register that holds your desired value, viz:

        clkset  rst
        ...
rst     long    $80

This behavior is defined in the Propeller Manual: "Mode (d-field) is the register containing the 8-bit pattern to write to the CLK register."

-Phil

ke4pjw

Someone PMed me this gem.

hubop $, #128

Works like a charm and does not require an extra register. Sweet!

--Terry

Phil Pilgrim (PhiPi)

That's pretty clever! Kuroneko, maybe?

-Phil

Peter Jakacki

Sounds like a trick a black cat would come up with neat
Ah ..... so much talent that has faded from the forum, and who could forget deSilva and many others?

ke4pjw

Twas the black cat indeed Phil, Peter, et al, I do miss the good old days on these forums. Glad you guys are still around.

Electrodude

ke4pjw wrote: »

Someone PMed me this gem.

hubop $, #128

Works like a charm and does not require an extra register. Sweet!

--Terry

That is clever. If anyone tries using this to clkset other values, note that the bottom 3 bits of the #128 must be zero, since they're what specifies that it's a clkset and not some other hubop.