CS8900a problems (very long post)

From: Kiran Vinta (ghettoman101_at_yahoo.com)
Date: 05/03/04 

Date: 2 May 2004 21:21:53 -0700

Currently, I am trying to interface the a cs8900a to the motorola 6812
microcontroller. A desecription and schematic of the board I am using
can be found at http://www.invector.nu/iet8900.asp. Additionally, I
have been using the cs8900a in 8 bit mode (or trying to). I am able
to read from registers or any place in internal memory using the
packetpage pointer and packetpage data registers (i.e. I can read the
product ID register). My main problem is that I I am unable to
transmit any packets. I am connecting my ethernet module to my pc via
a crossover cable. On my pc, I have an ethereal packet sniffer
running to see if I was able to send anything. Right now I am able to
get a bid for transmit (the RDY4txNow bit goes high) but it will not
transmit anything. Also when I put the while loop in for the repeated
transmit, the cs8900a will not reset and the link light will not come
on. If I comment out the while loop, the reset light does come on but
it still does transmit anything. I think it either may be compiler
problems or timing issues. How long must I wait after I reset to
start transmitting anything? I've looked in cirrus's 8-bit
application note for transmitting and I've read the data *** for
transmitting many times (section 5.7). Im really stumped so any help
will be appreciated.

Motorola ports - IET 8900a pins

PORTT[7:0] - AD[7:0]
PORTJ[7:4] - D[3:0]
PORTJ[0] - AEN
PORTJ[1] - IOR
PORTJ[2] - IOW

#include "HC12.h" //port maps

#define PPPtr 0x0a //address of packet page pointer
#define PPData 0x0c //address of packet page data register
#define RxTxData 0x00 // Receive/Transmit data (port 0)
#define RxTxData1 0x02 // Receive/Transmit data (port 1)
#define TxCmd 0x04 // Transmit Command
#define TxLength 0x06 // Transmit Length
#define ISQ 0x08 // Interrupt status queue
#define bkpt asm("bgnd");

//waits a time/4 ms
void mswait(unsigned short time){

  for(;time>0;time--){

    TC5=TCNT+2000; // wait

    TFLG1 = 0x20; // clear C5F

    while((TFLG1&0x20)==0){};
}
}

void TimerInit(void){

  COPCTL = 0x00; // disable COP
  TIOS |= 0x20; // enable OC5
  TSCR =0x80; // TEN(enable)

}

//changing the wait periods does not change the final data output
unsigned char IOread (unsigned char address)
{
        unsigned char data;
        DDRT = 0x00; //set port t as input
          PORTJ = ((address<<4)&0xF0) | 0x07; //put address on pins
          PORTJ &= ~0x01; //pulsing AEN
          PORTJ &= ~0x02; //IOR
        mswait(1); //wait
        data = PORTT; //capture data
          PORTJ |=0x02; //end pulse IOR
          PORTJ |= 0x01; //end pulse AEN
          return data;
}

//changing the wait periods does not change the final data output
void IOwrite (unsigned char address, unsigned char value)
{
        DDRT = 0xff; //set port as output
        PORTT = value; //Port T equals data value
        PORTJ = ((address<<4)&0xF0) | 0x07; //put address on pins
        PORTJ &= ~0x01; //pulsing AEN
        PORTJ &= ~0x04; //IOwrite
        PORTJ &= ~0x02;
        mswait(1);
        PORTJ |=0x02;
        PORTJ |=0x04; //end IOW
        PORTJ |= 0x01; //end pulse AEN
}

  unsigned char reading; //first byte for input
  unsigned char reading1; //second byte for input
  unsigned char BusST0, BusST1;
  unsigned char event0, event1;

void main(void){
  DDRH = 0xFF; //set Port H as outputs
  event0 = 0x00;
  reading = 0x00; //setting reading to zero
  reading1 = 0x00; //sertting reading1 to zero
  COPCTL = 0x00; //disable COP
 // SCI_Init(13); //initialize SCI interface
  TimerInit(); //initialize timer unit
  DDRJ = 0xff; //set port j as outputs
  PORTJ |= 0x07; //
  PORTH |= 0x01; //pulse reset
  mswait(1000); //250 ms
  PORTH &= ~0x01; //end pulse reset
// mswait(1);
  
  // Configure RxCTL fo Promiscious mode, RxOK
        // (1) Write 0x0104 to PacketPage Pointer
        // (2) Write 0x0180 to PacketPage Data Port
        IOwrite(PPPtr, 0x04);
        IOwrite(PPPtr + 1, 0x01);
        IOwrite(PPData, 0x80);
        IOwrite(PPData + 1, 0x01);

  
  
          // Set 10BaseT, SerRxOn, SerTxOn in LineCTL
        // (1) Write 0x0112 to PacketPage Pointer
        // (2) Write 0x00c0 to PacketPage Data Port
        IOwrite(PPPtr, 0x12);
        IOwrite(PPPtr + 1, 0x01);
        IOwrite(PPData, 0xc0);
        IOwrite(PPData + 1, 0x00);

        
  while (1)
  {
                // Send the transmit command
                IOwrite(TxCmd, 0xc0); //wait for whoel fram
                IOwrite(TxCmd + 1, 0x00);
                
                // 8 bytes to be sent
                IOwrite(TxLength, 0x04); //sending 8 byte
                IOwrite(TxLength + 1, 0x00);
                
                IOwrite(PPPtr, 0x38); //address of busST register
                IOwrite(PPPtr + 1, 0x01);

                
                // Bid for transmit
                do {
                   BusST0 = IOread(PPData);
                   BusST1 = IOread(PPData+1);
                }while(!(BusST1==0x01)); //check for rdy4txnow

                

                                                         
                IOwrite(RxTxData, 0x12); //sending test data
                IOwrite(RxTxData+1, 0x23);
                IOwrite(RxTxData, 0x45);
                IOwrite(RxTxData+1, 0x67);
                IOwrite(RxTxData, 0x89);
                IOwrite(RxTxData+1, 0xab);
                IOwrite(RxTxData, 0xcd);
                IOwrite(RxTxData+1, 0xef);

        }

}

-Kiran Vinta
ps Ive talked to the invector but they are very slow in responding.