PARALLEL MASTER PORT communication problem

[bikashh]

Hello Friends,
I am doing a project around PIC32MX675F512L in which I need to communicate with external RAM(IDT71V016SA) connected parallel. I am using "PARALLEL MASTER PORT (PMP)" for communication.
But when reading into a buffer from external RAM, all the locations gets filled with the last value being written in the write process. I checked the hardware but everything seem OK.

My code is as below:

mPMPEnable();
mPMPOpen(CONTROL, MODE1, PORT, INTERRUPT);
PMADDR = 0;
for (i=0; i<10; i++)
{
PMPMasterWrite(i);
buffer1=PMPMasterRead();
PMADDR++;
}
// PMADDR = 0;
for (i=0; i<10; i++)
{
buffer1 = PMPMasterRead();
PMADDR++;
}


Thank you in advance

 

[jayanth.devarayanadurga]

Why there is two for loops doing the same thing i.e., why the for loop is repeated twice?

 

[bikashh]

Thanks for the reply,

Actually the code is like this,

mPMPEnable();
mPMPOpen(CONTROL, MODE1, PORT, INTERRUPT);//interrupt is disabled

PMADDR = 0;
for (i=0; i<10; i++)
{
PMPMasterWrite(i);//I is the value I am writing to external RAM
PMADDR++; // incrementing RAM address
}

PMADDR = 0;
for (i=0; i<10; i++)
{
buffer1 = PMPMasterRead(); //reading from RAM 1st location and writing to buffer1
PMADDR++;
}


Tried different ways but failed.
Thanks

 

[jayanth.devarayanadurga]

Post the manual which explains the usage of mPMPOpen() function. Are you using C32, Hi-Tech C, or XC32 Compiler?

 

[bikashh]

I am using C32 compiler.

 

[jayanth.devarayanadurga]

mPMPOpen(PMP_ON | PMP_READ_WRITE_EN, PMP_MODE_MASTER_1 | PMP_AUTO_ADDR_INC, PMP_PEN_ALL, PMP_INT_OFF)

Post your full code and also the circuit showing interfacing of the external device to PMP port. What external device is interfaced?