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NickSim
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| Texas Instrument RS232 work but maxim RS232 doesn't work? |
 Posted: Thu Apr 02, 2009 1:21 pm |
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I try to use maxim RS232 for serial communication betwwen PIC and PC.
I have tried my circuit with 2 pcs of maxim RS232 IC but both not working (cannot send data to hyper terminal). When I use back the Texas Instrument RS232, the PIC able to send data successfully to PC via hyper terminal. So, what is the problem with maxim RS232? Thanks. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Apr 02, 2009 1:25 pm |
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We are not mind readers. Post the part numbers.
Also, this is not really a CCS compiler question. |
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NickSim
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| Posted: Thu Apr 02, 2009 1:38 pm |
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Texas Instrument MAX232N and Maxim Max232CPE
It is not really related to ccs but I just want to know if someone ever encounter this problem before and how to solve it. I don't think it is the code problem. Your help will be very much appreciated. |
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asmallri
Joined: 12 Aug 2004
Posts: 1634
Location: Perth, Australia
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| Posted: Thu Apr 02, 2009 1:54 pm |
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| NickSim wrote: | Texas Instrument MAX232N and Maxim Max232CPE
It is not really related to ccs but I just want to know if someone ever encounter this problem before and how to solve it. I don't think it is the code problem. Your help will be very much appreciated. |
Assuming you are using a +5volt supply, measure the voltage on pics 2 wrt ground and 6 wrt ground. They should be +8.5 volts and - 8.5 volts respectively.
If not then... Check the power and supply connections to the chip and ensure the +5 volt rail is + 5 volts. Check that the capacitors are soldered correctly (no dry joints). If using tantalum capacitors then ensure they are installed the correct way around.
_________________
Regards, Andrew
http://www.brushelectronics.com/software
Home of Ethernet, SD card and Encrypted Serial Bootloaders for PICs!! |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Thu Apr 02, 2009 7:56 pm |
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some max232 equivalents use 1 uf cap others use .1uf caps
i dont' know what happens if you use the kind that need 1 uf - with just .1 uf
or vice versa but that could be checked
have you LOOKED to see the output levels coming OUT of the chip
on the TX out ?
and More telling
do BOTH directions fail ?
meaning no xmit or receive ?
or just XMIT failing ? |
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