EZ340 RF2500 packet question

Hi all:

I am trying to send packets between two targets boards. The packet length is set to be 64.

Then:

SPI_Write_Single(SINGLE_TX,0x0F);               //Write some data to the singal TX buffer

SPI_Strobe(STX);                //Signal for transmittion

while(!(P2_6));                     //Wait for Sync word to be sent

while(P2_6);                       //Wait for packet to finish

On the receiver board,

SPI_Strobe(SRX);           //Signal for receiving

while(!(P2_6));                     //Wait for Sync word to be sent

while(P2_6);                       //Wait for packet to finish

c = SPI_Read_Single(SINGLE_RX)       //Read the data we just received.

But as soon as the sample data I send exceeds 0x0F. c will be equal to zero. Below 0x0F. it was fine.

Anyone know why?

Thanks