TMS320F28035: Mysterious SPIFFRX.bit.RXFFST words

Part Number: TMS320F28035

I have slightly altered a loopback SPI example provided by TI to remove the loopback and access a MCP23S08 (IOExpander) chip. I have some initial setup of the 23S08 and then I loop thru all the outputs turning on some leds. All works as expected except I am getting an increment in the SPIFFRX.bit.RXFFST field for the first 4 SPI writes to the 23S08 and then it stops incrementing. If I do the reads of the SpiaRegs.SPIRXBUF, I get just 0xFF and the RXFFST will decrement to 0. RXFFST only counts to 4 and if I do not read them on the next cycle, the value will not increment any further. So after I read all the buffer data and RXFFST = 0, RXFFST will increment to 4 again based on the next 4 SPI writes.
I will supply images that show no activity on the SOMI line to the F28035.
As a means of troubleshooting, I even disconnected the SOMI line from the 23S08 and get the same result - RXFFST counts to 4 based on the next 4 SPI writes to the 23S08.
The SPI writes are:
0x40 - 23S08 address and Wr command - RXFFST increments to 1
0x10 - 23S08 OLAT register - RXFFST increments to 2
0xyy - yy is the bit pattern for the OLAT register - turn LED on or off - RXFFST increments to 3
0x40 - 23S08 address and Wr command - start of another series of SPI writes - RXFFST increments to 4
0x10 - 23S08 OLAT register - RXFFST remains at 4
0xyy - yy is the bit pattern for the OLAT register - RXFFST remains at 4
...

1 image is a complete cycle of 14 23S08 SPI writes, 1 image shows first 5 SPI writes and 1 image shows 1 SPI write with the channel names.

Important code:

void main(void)
{
Uint16 rdata; // received data
int i = 0;
int readbytes = 0;

InitSysCtrl();

InitSpiaGpio();

DINT;

InitPieCtrl();

IER = 0x0000;
IFR = 0x0000;

InitPieVectTable();

spi_fifo_init(); // Initialize the Spi FIFO
spi_init(); // init SPI
mcp23s08_init(); // init mcp23s08

for(;;)
{
// Transmit data
led_flash( );

while(SpiaRegs.SPIFFRX.bit.RXFFST == 0 ) { }
readbytes = SpiaRegs.SPIFFRX.bit.RXFFST;
for (i = 0; i < readbytes; i++)
{
// Check against sent data
rdata = SpiaRegs.SPIRXBUF;
// if(rdata != sdata) error();
}
}
}

void error(void)
{
__asm(" ESTOP0"); // Test failed!! Stop!
for (;;);
}

void spi_init()
{
// If only sending a byte at a time, CCR.SPICHAR = 7 (8 bits = 1 byte)
// so to populate SPITXBUF, left-justify the byte so to send 0x41, SPITXBUF = 0x4100
SpiaRegs.SPICCR.all =0x0007; // Reset on, rising edge, 8-bit char bits
SpiaRegs.SPICTL.all =0x0006; // Enable master mode, normal phase,
// enable talk, and SPI int disabled.
SpiaRegs.SPIBRR = 0x001D; // 1Mhz SPI clk
SpiaRegs.SPICCR.bit.SPISWRESET = 1; // Relinquish SPI from Reset
SpiaRegs.SPIPRI.bit.FREE = 1; // Set so breakpoints don't disturb xmission
}

void spi_fifo_init()
{
// Initialize SPI FIFO registers
SpiaRegs.SPIFFTX.bit.TXFIFORESET= 0;
SpiaRegs.SPIFFRX.bit.RXFIFORESET= 0;
SpiaRegs.SPIFFTX.all=0xC040;
SpiaRegs.SPIFFRX.all=0x6040;
SpiaRegs.SPIFFCT.all=0x0;
SpiaRegs.SPIFFTX.bit.TXFIFORESET= 1;
SpiaRegs.SPIFFRX.bit.RXFIFORESET= 1;
}

void mcp23s08_init( )
{
// Set all GPIO as outputs
SpiaRegs.SPITXBUF= WRITE_CMD << 8;
SpiaRegs.SPITXBUF= MCP_IODIR << 8;
SpiaRegs.SPITXBUF= 0x0000;
delay_loop(200);
// Set all GPIO polarity
SpiaRegs.SPITXBUF= WRITE_CMD << 8;
SpiaRegs.SPITXBUF= MCP_IPOL << 8;
SpiaRegs.SPITXBUF= 0x0000;
delay_loop(200);
}

void led_flash( )
{
int led = 0;
// Turn off/on LEDs
for (led = 0; led <= 6; led++)
{
SpiaRegs.SPITXBUF= WRITE_CMD << 8;
SpiaRegs.SPITXBUF= MCP_OLAT << 8;
SpiaRegs.SPITXBUF= 1 << (8 + led);
DELAY_US(200000);
}
for (led = 7; led >= 1; led--)
{
SpiaRegs.SPITXBUF= WRITE_CMD << 8;
SpiaRegs.SPITXBUF= MCP_OLAT << 8;
SpiaRegs.SPITXBUF= 1 << (8 + led);
DELAY_US(200000);
}
// Read 23S08 GPIO pins
/*
SpiaRegs.SPITXBUF= READ_CMD << 8;
SpiaRegs.SPITXBUF= MCP_GPIO << 8;
SpiaRegs.SPITXBUF= 0x0000;
delay_loop(200);
*/
}