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flint
Joined: 05 Jun 2010
Posts: 24
Location: Nigeria
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| easyBee |
 Posted: Thu Jan 12, 2012 7:55 pm |
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Hi everyone, I am working on a project that requires wireless communication between two PIC's. I tested a simple program on the PIC's using hardware UART (wired) and its working clock is 20MHz whenever I try to connect them using easyBee module (from MikroEletronika ) nothing works.
I used a baudrate of 9600, later changed to 38400, 57600, none worked.
I connected the tx & rx pins of PIC to the TX&rx pins of the easyBee, it still did not work. I used the tx, rx, 5v, GRnd pins of the easyBee only. Any help would be appreciated.
Best regards. |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Fri Jan 13, 2012 6:18 pm |
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| you are most likely tangled up in 3v/5v non level translated misery IMHO |
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flint
Joined: 05 Jun 2010
Posts: 24
Location: Nigeria
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| Posted: Fri Jan 13, 2012 7:53 pm |
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| asmboy wrote: | | you are most likely tangled up in 3v/5v non level translated misery IMHO |
Thanks for your response, please can you explain what you meant by that,this is the connection i used:
easyBee Module has the following pins:
TX
RX
RTS
CTS
5V....... I powered the module from a 5v supply from lm7805 voltage regulator
GRND
PIC------->Transmitter
TX------------TX
RX------------ RX
after much trial with no progress, i tried the other way round, i.e
TX-----RX
RX------TX
still not working. |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Fri Jan 13, 2012 10:18 pm |
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the RX return side is at 3v levels - may not reliably toggle the receive side
pins on each pic |
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flint
Joined: 05 Jun 2010
Posts: 24
Location: Nigeria
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| Posted: Sat Jan 14, 2012 7:33 pm |
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| asmboy wrote: | the RX return side is at 3v levels - may not reliably toggle the receive side
pins on each pic |
you are right, i checked the voltages at the various pins with a multimeter and these are the outcome:
EasyBee(powered but not connected to pic)
TX = 3V,
RX = 5V,
RTS = 3V.
CTS = 0V,
SUPPLY = 5V,
GRND
PIC(Powered up, but not connected the easyBee):
TX = 3V,
rx = 0v,.... (transmitting PIC)
I have two easybee modules, and two PIC's for transmit and receive, respectively. How do I connect the TX and RX pins of the PIC's to the easybee. please, how do i maneuver my way around the voltage translations? |
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temtronic
Joined: 01 Jul 2010
Posts: 9246
Location: Greensville,Ontario
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| Posted: Sat Jan 14, 2012 8:52 pm |
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You have a couple options
1) use a Low voltage PIC ( those like 18LFxxxx, 16LFxxxx). the L means it's designed to work on 3 volts.
2) add a level translator interface between the 5 volt PIC and the 3 volt peripheral. This could be a simple transistor/resistor circuit or a 'chip' designed for this purpose.
Depending on your parts supply, either will work you MUST do one of them. |
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