CS8900a problems (very long post)

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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 sheet 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]

#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){


    TC5=TCNT+2000;  // wait

    TFLG1 = 0x20;   // clear C5F


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;
    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.

Re: CS8900a problems (very long post)
Quoted text here. Click to load it

To see if there are compiler problems, look at the code generated by your
compiler and see if it matches what you intended. Most compilers can produce
combined assembly/C listings. Some debuggers also provide this.

Quoted text here. Click to load it

Try section 3.3 of the datasheet - "Reset and Initialization".

Another helpful document might be the CS8900a FAQ at Cirrus Logic's website.

Re: CS8900a problems (very long post)
I have looked at those documents but they still do not help me very much.  

snipped-for-privacy@aol.com (Gary Kato) wrote in message
Quoted text here. Click to load it

Re: CS8900a problems (very long post)

Adam Dunkels uIP package supports the CS8900a. Check out his source code.

http://www.sics.se/~adam/uip /

It is written in C with some embedded 6502 assembler.

Perhaps that might be helpful to you.


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