ECIO40P IOC

[Steve001]

Morning All

Using IOC 0 & 1 on an ECIO40P, is there any gotcha's to be aware of?
On my ECIO sometimes didn't pic up the change of state

Program is a test rig that detects two relays changing state then records the voltage that the relay has changed

Steve

[QMESAR]

Hi Steve,
I assume the ECIO40 use a PIC18 ,Long time I did not use the IOC feature on these MCU's but I recall some how when using the
IOC pin you need to read the whole port and then mask out which pin changed .otherwise it is not working stable
I might be wrong however worth wile to try or confirm from the Datasheet

Good luck

[medelec35]

Hi Steve,
Have you post the correct flowchart?
At the end of main there is just a call maro that had not been assigned!
So the code will just stop with nothing on the display at all.
Also within lvd_test macro there is

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CountRB0 = 1

At the end of that branch is

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CountRB0 = 0

clearing the CountRB0 flag.
Then further down you have another

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CountRB0 = 1

Since the CountRB0 has already been cleared it will be hit and miss where this will be accessed or not.
It will depend on what point the INT0 has been triggered?
However since this macro has not been called, it will not show anything on the display at all.
Same with

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 countRB1 = 1

, it's decision branch as been duplicated as well!

[Steve001]

Hi Martin,

Hi Steve, >Have you post the correct flowchart?

opps no I haven't, I think I have found my issue also gone back to think about it.

the relay's react to a falling voltage level I have a couple of boards that I can plug in to the test rig so I have different readings.
they are as is from our PCB manufacturer.
The set points where very close to each other and the wrong way round. (0.8 volts, trip signal happened first, then alarm)

the RB0 & RB1 counter was an attempt to keep the voltage readings for "alarm" and "trip" and detect if the interrupt had happened incase a relay didn't operate.

It will depend on what point the INT0 has been triggered?

not sure what you mean

Theory of operation example

Incoming voltage range 27.4 - 22 volts DC. Start at 27.3 volts
Reduce voltage
PCB Alarm relay de energises @ 23.8 Volts DC
Further reduce voltage
PCB Trip relay de energises @ 22.8 Volts DC

my understanding of an interrupt - more than likely wrong

when IOC pin changes state the interrupt will then go away from the main program do something else then return ?

Steve

:Edit - found another IOC example on the WIKI going to have another play with this also