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xyzsor
Joined: 19 Dec 2010
Posts: 12
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| how to use PORTE and pinA4 of pic16f877a as output ? |
 Posted: Mon Jan 31, 2011 10:18 am |
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Hi guys. I'm quite new in uC programming. I'm using a pic16f877a.
I need to use pin A4 and port E as a TTL output.
Is that possible? What configurations do I need to set?
The only ones I triggered are the ff.
| Code: |
#byte porta=5 /* defines memory location of register */
#byte porte=9 /* defines memory location of register */
set_tris_a(0x00);
set_tris_e(0x00);
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Thanks in advance to anyone who helps. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19552
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| Posted: Mon Jan 31, 2011 11:24 am |
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You don't need any of what you have posted.
Just:
| Code: |
output_a(value);
output_e(value);
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Where 'value' is what you want to output. The compiler does _all_ the nitty gritty stuff for you, setting the TRIS automatically, and outputting the value to the right port.
On your chip, A4, is a 'pull down' pin only. You have to add an external pullup resistor to use it as a normal output.
On portE, make sure you have turned off the PSP.
Best Wishes |
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dyeatman
Joined: 06 Sep 2003
Posts: 1934
Location: Norman, OK
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| Posted: Mon Jan 31, 2011 11:35 am |
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They might need to turn off the comparators and ADCs
| Code: |
setup_adc(ADC_OFF);
setup_comparator(NC_NC_NC);
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_________________
Google and Forum Search are some of your best tools!!!! |
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xyzsor
Joined: 19 Dec 2010
Posts: 12
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| Thx |
| Posted: Mon Jan 31, 2011 11:41 am |
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| Cool. I never knew it was that simple. Thanks Ttelmah for the heads up. People in this forum are very helpful. |
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