MCP23x08 reset pin

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js
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Posted by js: Sun. Aug 12, 2012 - 01:37 AM
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I don't think I understand what's going on with the reset pin.

The datasheet http://ww1.microchip.com/downloa... talks about the POR resetting the chip to it's default state, which I understand, but it says nothing about what the reset pin does.

Does it work like the POR or simply resets any I/O pin set as output to zero? :roll: (I hope the later)

This would be similar to the MCP23x16 or MCP23x17 both the I2C version which I'm using or the SPI version.

Does anyboby have any ideas? It's Sunday and I'm trying to finish off some PCB artwork and my not-so-friendly?? (other company) FAE will not be in the office until tomorrow.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Learning and Information, General Electronics
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valusoft
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Posted by valusoft: Sun. Aug 12, 2012 - 02:52 AM
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John, if you do the crime, expect to do the time :lol:

Doesn't figure 2.2 help? It sort of says to me that that the internal reset is generated separately by both the power on sequence and the external reset and both produces the same result.

Enjoying a quiet Sunday while "the wife" goes to the football with her girlfriend. Maybe getting together afterwards with her Italian husband for a bowl of linguine. Yumm.

Cheers,

Ross

Ross McKenzie ValuSoft Melbourne Australia

Last Edited: Sun. Aug 12, 2012 - 03:08 AM
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js
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Posted by js: Sun. Aug 12, 2012 - 03:00 AM
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Haha but this is not a micro controller, it's just a peripheral chip. :-)

If no one has the answer I will need to wait for tomorrow. Anyway even though Atmel and the other company are rivals they must use the same web developers, their website is just as useless when it comes to find anything!

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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valusoft
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Posted by valusoft: Sun. Aug 12, 2012 - 03:10 AM
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Mine edited.

Ross McKenzie ValuSoft Melbourne Australia

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js
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Posted by js: Sun. Aug 12, 2012 - 07:21 AM
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It seems to show that the reset pin resets the output pin(s). However it may NOT reset the direction on the pins to the POR value, maybe all inputs??

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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mnehpets
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Posted by mnehpets: Sun. Aug 12, 2012 - 11:07 AM
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js wrote:
It seems to show that the reset pin resets the output pin(s). However it may NOT reset the direction on the pins to the POR value, maybe all inputs??

table 1-3 gives the RST value for dir IODIR register as all 1s. That implies that the reset pin will change the IO pins back to inputs.

- S

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js
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Posted by js: Sun. Aug 12, 2012 - 10:21 PM
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I'll harass the FAE this morning or simply get a couple of chips to play with.

The boards will not be here for a couple of weeks and I have made provisions for the reset pin to be wired to an I/O pin, so I should be covered.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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