Resetting the POS on a FIFO

simonjh · Nov 9, 2017

Hello,

I'm trying to add a button to a HMI to reset the count of the POS on the FFL instruction due to things getting out of sync. Can anyone help me out??

Cheers!

jkerekes · Nov 9, 2017

A RES instruction?

Phrog30 · Nov 9, 2017

Why can't you just write (MOV) a new value, either zero or another value to a specific position?

simonjh · Nov 9, 2017

I don't believe you can MOV a 0 to the position unless there is some sort of trick to it. With the RES instruction what do I reference it to?

Phrog30 · Nov 9, 2017

simonjh said:
I don't believe you can MOV a 0 to the position unless there is some sort of trick to it.

Trick? No, just do it.

GaryS · Nov 9, 2017

you can move any value into the pos of a FIFO within the rage of the file
but it will not take effect until the next time the rung goes from false to true then it will add or sub 1 depending if its a load or unload.
if the number is outside the file size the processor will fault out

James Mcquade · Nov 10, 2017

Do you have an unload statement associated with the FFL?
if so, does that also need to be changed?

james

Phrog30 · Nov 10, 2017

James Mcquade said:
Do you have an unload statement associated with the FFL?
if so, does that also need to be changed?

james

It should share the same control, so any change is for both.

GaryS · Nov 10, 2017

both the load and unload use the same control word so if you change on you automatically change the other.
the load is always at word 0 unload can be from any word in the file
you have to trigger either the load or unload if you change the position so that it moves the data.
you can also access the file used in the FIFO directly to read or write data to the file

James Mcquade · Nov 10, 2017

Thanks for the info.

I forgot.

james

Resetting the POS on a FIFO

simonjh

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jkerekes

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Phrog30

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simonjh

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Phrog30

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GaryS

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James Mcquade

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Phrog30

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GaryS

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James Mcquade

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