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aaronik19
Joined: 25 Apr 2011
Posts: 297
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| MCP23008 reading port |
 Posted: Sat May 11, 2013 6:07 pm |
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hello friends,
I have the following code:
| Code: | MCP23008_write(MCP23008_3_write, _IODIR, 0xFF); // All Pins are Inputs
MCP23008_write(MCP23008_3_write, _IPOL, 0x00); // All Outputs are similar to inputs
MCP23008_write(MCP23008_3_write, _GPINTEN, 0xFF); //All Interrupt on Change
MCP23008_write(MCP23008_3_write, _DEFVAL, 0x00); //To Compare GPINTEN & INTCON against DEFVAL
MCP23008_write(MCP23008_3_write, _INTCON 0xFF); //Compare with 0 value
MCP23008_write(MCP23008_3_write, _IOCON, 0x02); //int active high
MCP23008_write(MCP23008_3_write, _GPPU, 0x00); // Disable Pull-Up Resistors
MCP23008_write(MCP23008_3_write, _INTF, 0x00);
MCP23008_write(MCP23008_3_write, _GPIO, 0x00);
MCP23008_write(MCP23008_3_write, _OLAT, 0x00); |
the problem is that the setup is good but the interrupt is not being fired. I am sending this code to setup the MCP23008 as input (read) on Interrupt change. I read all the datasheet and related application note but still in the same problem. Can someone please guide me if I've setup the MCP23008 correctly?
Thanks |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Sun May 12, 2013 11:36 am |
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without source code for
MCP23008_write()
and how you use it in MAIN()
how can anybody tell what
is going on ?? |
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aaronik19
Joined: 25 Apr 2011
Posts: 297
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| Posted: Sat Mar 01, 2014 10:26 pm |
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dear all,
I continue to work on this chip and still have problems to clear interrupt when read the INTCON register. This is the driver code:
| Code: | FUNCTIONS DEFINITIONS
#define MCP23008_1_write 0x4E
#define MCP23008_1_read 0x4F
#define MCP23008_2_write 0x48
#define MCP23008_2_read 0x49
#define MCP23008_3_write 0x4C
#define MCP23008_3_read 0x4D
// MCP23008 REGISTERS
#define _IODIR 0x00 // determines if the pin is input or output
#define _IPOL 0x01 // the polarity of the input. Can have invert input
#define _GPINTEN 0x02 // interrupt on change input
#define _DEFVAL 0x03 // default comparision
#define _INTCON 0x04 // compare with the DEFVAL during interrupt
#define _IOCON 0x05 // I/O Expander configuration
#define _GPPU 0x06 // pull-up resistors
#define _INTF 0x07 // interrupt flag
#define _INTCAP 0x08 // capture the state of the port during interrupt
#define _GPIO 0x09 // actual input/outputs on the port
#define _OLAT 0x0A // logic level register of the output port
long int MCP23008_read(unsigned int WriteAddress, unsigned int cmdByte, unsigned int ReadAddress)
{
unsigned int data;
i2c_start(); // start condition
delay_us(20);
i2c_write(WriteAddress); // Send slave address and clear (R/W_)
delay_us(20);
i2c_write(cmdByte); // Command byte and register to be written.
delay_us(50);
i2c_start();
delay_us(20); // restart condition
i2c_write(ReadAddress); // Send slave address and clear (R_/W)
delay_us(20);
data = i2c_read(); // Data from LSB or MSB of register
delay_us(20);
i2c_stop(); // stop condition
return(data);
}
void MCP23008_write(unsigned char location, unsigned char addr, unsigned char data)
{
i2c_start();
delay_us(20);
i2c_write(location);
delay_us(20);
i2c_write(addr);
delay_us(20);
i2c_write(data);
delay_us(20);
i2c_stop();
delay_us(20);
}
void MCP23008_init()
{
output_float(PIN_C4);
output_float(PIN_C3); //signals to prepare MCP for operation
delay_ms(250); //delay for MCP23008 start-up
MCP23008_write(MCP23008_1_write, _IODIR, 0x00); // All Pins are Outputs
MCP23008_write(MCP23008_1_write, _IPOL, 0x00); // All Outputs are similar to inputs
MCP23008_write(MCP23008_1_write, _IOCON, 0x00);
MCP23008_write(MCP23008_2_write, _IODIR, 0x00); // All Pins are Outputs
MCP23008_write(MCP23008_2_write, _IPOL, 0x00); // All Outputs are similar to inputs
MCP23008_write(MCP23008_2_write, _IOCON, 0x00);
MCP23008_write(MCP23008_3_write, _IODIR, 0xFF); // All Pins are Inputs
MCP23008_write(MCP23008_3_write, _IPOL, 0x00); // All Outputs are similar to inputs
MCP23008_write(MCP23008_3_write, _GPINTEN, 0xFF); //All Interrupt on Change
MCP23008_write(MCP23008_3_write, _DEFVAL, 0x00); //To Compare GPINTEN & INTCON against DEFVAL
MCP23008_write(MCP23008_3_write, _INTCON 0xFF); //Compare with Defcal Register
MCP23008_write(MCP23008_3_write, _IOCON, 0x0A);
MCP23008_write(MCP23008_3_write, _GPPU, 0x00); // Disable Pull-Up Resistors
MCP23008_write(MCP23008_3_write, _IOCON, 0x00);
MCP23008_write(MCP23008_3_write, _GPIO, 0x00);
MCP23008_write(MCP23008_3_write, _OLAT, 0x00);
} |
the main code is:
| Code: | #include <program.h>
#include <mcp23008.c>
//VARIABLES FOR THE PROGRAM
int counter1 = 0;
int GP_count = 0;
int8 read_port = 0;
#INT_EXT
void EXT_isr(void)
{
output_high(PIN_D1);
output_high(PIN_D2);
read_port = MCP23008_Read(0x4C,0x08, 0x4D);
output_low(PIN_D1);
mcp23008_write(0x48, 0x09, read_port);
output_low(PIN_D2);
}
void main()
{
mcp23008_init();
enable_interrupts(INT_EXT);
ext_int_edge( H_TO_L );
enable_interrupts(GLOBAL);
while(TRUE)
{
}
} |
I also draw the circuit on proteus but this is real simulation and not software simulation. Used proteus only to show the circuit
http://postimg.org/image/47llzictt/ |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sat Mar 01, 2014 10:38 pm |
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| Quote: |
data = i2c_read(); // Data from LSB or MSB of register |
This is the same old problem. It's missing the NAK on the last i2c_read
in your MCP23008_read() function.
In your thread here, from 2011, you had the NAK in there. Why did
you take it out in your latest code ? It's essential:
http://www.ccsinfo.com/forum/viewtopic.php?t=46502
In this thread here, which looks like the place you got the driver from,
he makes the missing NAK mistake and I correct it:
http://www.ccsinfo.com/forum/viewtopic.php?t=22639 |
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aaronik19
Joined: 25 Apr 2011
Posts: 297
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| Posted: Sun Mar 02, 2014 12:09 am |
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thanks I solve that problem. I forgot the "0"...thanks
But the problem is that When I press the button, the interrupt is working and it is being written on the second MCP chip. The problem is that when I press another button nothing is happening. ON the datasheet it is mentioned that when the register INTCON (0x08) is being read, the interrupt will be reset. Do I missing something please? |
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aaronik19
Joined: 25 Apr 2011
Posts: 297
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| Posted: Sun Mar 02, 2014 9:29 am |
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| Afterr more time trying, i am still have no success....any help please? |
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Mike Walne
Joined: 19 Feb 2004
Posts: 1785
Location: Boston Spa UK
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| Posted: Sun Mar 02, 2014 2:16 pm |
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Reduce your code to a few lines so showing us what your real problem is.
Mike |
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