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payam
Joined: 15 Nov 2005 Posts: 42
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Posted: Wed Jun 13, 2007 6:43 pm Post subject: I2c and problem with distance |
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Hello every one
i have one question.please help me about it.
i want contact nineteen micro together. and i want use I2C protocol, distance of master to first slave is about 1.5 meter and distance second slave of first slave is about 50 cm and this distance(50 cm) between slave micro continue until eighteenth slave.
i want to know which IC or circuit can help me to use this protocol(I2C) with this distance between micros
i select atmega 32 for master and atmega 8 for slave
thank you |
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kimmi
Joined: 24 Feb 2006 Posts: 1922 Location: Denmark
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Posted: Thu Jun 14, 2007 10:32 am Post subject: |
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Hi payam,
Maybe you can use this take a look :
From maxim DS28EA00
@ EDIT : Ups this was for temperatur my mistake sorry ... but a nice chip _________________ / Kim
Last edited by kimmi on Thu Jun 14, 2007 11:07 am; edited 1 time in total |
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Luciano
Joined: 29 Nov 2004 Posts: 3149 Location: Italy
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payam
Joined: 15 Nov 2005 Posts: 42
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Posted: Thu Jun 14, 2007 11:10 am Post subject: have problem in finding this IC |
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hi every one
thank you for messages, but this Ic dont find in my country please help me in another way
best regard |
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ex4
Joined: 13 Jan 2006 Posts: 1062 Location: indonesia
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Posted: Thu Jun 14, 2007 1:33 pm Post subject: |
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for 50cm use the one tips like in the bascom avr help file on using i2c section (it said 80cm at 400kHz) |
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Luciano
Joined: 29 Nov 2004 Posts: 3149 Location: Italy
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Posted: Thu Jun 14, 2007 3:50 pm Post subject: |
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Ex4,
The distance between the master and last slave ( #18 ) is 10 meters
which is too much for I2C. You can extend the length of a I2C bus
if you use bus extender chips like the P82B715. (Expensive).
The slaves are ATmega8 chips so why not use RS485?
Best regards,
Luciano |
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payam
Joined: 15 Nov 2005 Posts: 42
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Posted: Thu Jun 14, 2007 10:51 pm Post subject: |
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thank you every one for all messages |
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ex4
Joined: 13 Jan 2006 Posts: 1062 Location: indonesia
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Posted: Fri Jun 15, 2007 12:06 am Post subject: |
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ups, sorry, forgotten that
oh yes, using rs485 is more easy and cheap to do |
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