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doryme
Joined: 16 Oct 2010
Posts: 20
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| problem with 16f877a..write and read from external memory |
 Posted: Sat Nov 27, 2010 5:12 am |
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Hello
I am using PIC16F877A. I want to write 8 bits in external memory, then read them again.
I enter 8 bits using 8 switches on PORTB, and read them on 8 leds on PORTD.
This is my simulation and my code(I am beginner  ) :
| Code: | #INCLUDE <16F877A.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#BYTE ADCON0=0x00
#BYTE ADCON1=0x07
#USE DELAY (CLOCK=10000000)
void main()
{
byte data0;
byte data1=0b00000000;
set_tris_b(0b11111111);
set_tris_a(0b11111111);
set_tris_e(0b00000000);
set_tris_d(0b00000000);
while(1)
{
if(input(pin_a0)&&!input(pin_a1))
{
set_tris_c(0b00000000);data0=input_b();output_c(data0);output_low(pin_e0);output_high(pin_e1);
}
else if(!input(pin_a0)&&input(pin_a1))
{
set_tris_c(0b11111111);output_high(pin_e0);output_low(pin_e1);data0=input_c();output_d(data0);
}
else
{
output_high(pin_e0);output_high(pin_e1);output_d(data1);
}
}
} |
The simulation works correctly, but why I get the error above? |
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temtronic
Joined: 01 Jul 2010
Posts: 9243
Location: Greensville,Ontario
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| Posted: Sat Nov 27, 2010 11:49 am |
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According to the datasheet, page 13, memorymap....
...address 009cx is NOT implemented (it physically does NOT exist).
Now as to WHERE your program does this....sorry, I only work with real hardware, not simulators.
However, since you are new...get rid of all those TRIS... functions, let the compiler handle it.
It is better to put one command/fucntion per line NOT all jammed up into one line with a buch of ;;;;;s ! It'll be easier to read and figure out what is going on !
Also use comments ! You might know what a line is doing now, but others don't and a day or two from now, you'll forget or mistake what that line is for. Been there- done that. When I code in assembly EVERY line has a comment, even obvious ones like clearing registers. With C I relax a bit, but not much.
Also it will help you to define NAMES to I/O pins. Again, something like RAM_OE is easier to understand what it's for than just PIN_E0.
The cleaner, neater, self-documented the code the easier it is in the long run. |
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doryme
Joined: 16 Oct 2010
Posts: 20
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| Posted: Sat Nov 27, 2010 3:51 pm |
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| temtronic wrote: | According to the datasheet, page 13, memorymap....
...address 009cx is NOT implemented (it physically does NOT exist).
Now as to WHERE your program does this....sorry, I only work with real hardware, not simulators.
However, since you are new...get rid of all those TRIS... functions, let the compiler handle it.
It is better to put one command/fucntion per line NOT all jammed up into one line with a buch of ;;;;;s ! It'll be easier to read and figure out what is going on !
Also use comments ! You might know what a line is doing now, but others don't and a day or two from now, you'll forget or mistake what that line is for. Been there- done that. When I code in assembly EVERY line has a comment, even obvious ones like clearing registers. With C I relax a bit, but not much.
Also it will help you to define NAMES to I/O pins. Again, something like RAM_OE is easier to understand what it's for than just PIN_E0.
The cleaner, neater, self-documented the code the easier it is in the long run. |
Hello
Thank you for your help.
I connected the circuit on breadboard and it works very well!
I will the notes you said about my code in my mind for next times! |
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