 |
 |
| View previous topic :: View next topic |
| Author |
Message |
doryme
Joined: 16 Oct 2010
Posts: 20
|
| problem with 16f877a..write and read from external memory |
 Posted: Sat Nov 27, 2010 5:12 am |
 |
|
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? |
|
 |
temtronic
Joined: 01 Jul 2010
Posts: 9170
Location: Greensville,Ontario
|
|
| Posted: Sat Nov 27, 2010 11:49 am |
|
|
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. |
|
|
doryme
Joined: 16 Oct 2010
Posts: 20
|
|
| Posted: Sat Nov 27, 2010 3:51 pm |
|
|
| 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! |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ 
Search
Register
Profile 
Log in to check your private messages 
Log in
