EM4095 Driver Problem!!

[micro]

Hello There,

I am trying to use em4095 chip with CCS picc compiler driver. I am using 18f2320 and 10MHz xtal in H4 mode. But I dont understand a few points in driver.

Firtstly, in CCP1 interrupt suvroutine in em4095.c, there is a line that is not so clear. I am giving the code snipped below

#INT_CCP1
void isr_ccp1()
{
int8 width;

//printf("Interrupt girisi\n\r");
// Toggle between capturing rising and falling edges to meausure width
if(RE_FE_TOGGLE)
{
setup_ccp1(CCP_CAPTURE_FE);
RE_FE_TOGGLE = 0;
}
else
{
setup_ccp1(CCP_CAPTURE_RE);
RE_FE_TOGGLE = 1;
}

// Calculate the width
width = CCP_1 - old_clock;
old_clock = CCP_1;
//printf("Old Clock : %d",old_clock);


switch(RF_readMode)
{
// Use to receive manchester formatted data from a transponder
case RF_MANCHESTER_DATA:
{
if(width > 54) // Check for a phase change
{
bitValue = ~bitValue; // Invert the save bit value
storeData = TRUE; // Force a bit store
}


In code snipped above, there is a line as " if(width > 54) ". Why does this value compare with 54. What does 54 mean? Why we use 54 as comrison.

Secondly, in em4095.c, there is a function like below :

void rf_init()
{
output_low(RF_SHD);
output_low(RF_MOD);

setup_timer_1(T1_EXTERNAL | T1_DIV_BY_1);
setup_ccp1(CCP_CAPTURE_RE);
setup_ccp2(CCP_COMPARE_INT);

setup_timer_0(RTCC_INTERNAL | RTCC_DIV_256);
enable_interrupts(INT_RTCC);
enable_interrupts(GLOBAL);
}

In code snipped above, there is a line as "setup_timer_0(RTCC_INTERNAL | RTCC_DIV_256);" . For this driver file, what clock frequency of microcontroller should we use. How can I use this driver in 10MHz H4 and 18fxxx family.

If you give me any reply, I would be gratefull. If you send some sample code snipped, It will be very usefull. Thank you for your interests.

[PCM programmer]

When CCS created the EM4xxx.C driver files for the RFID products
they must have also made some test program, to prove that the
drivers work. The test program is probably named EX_RFID.C, or
something like that. For some reason, they forgot to include it in the
compiler example files.

I think you should email CCS support and ask them if they will give
you the example programs that they used to test their EM4102.C,
EM4150.C, and EM4095.C drivers.

http://www.ccsinfo.com/techsupport.shtml

[ram]

How can i give the Selective Read Command to EM4150