如下面配置，中断触发不了
EALLOW;
PieVectTable.SPIA_RX_INT = &spiRxFifoIsr;
PieCtrlRegs.PIECTRL.bit.ENPIE = 1; // Enable the PIE block
PieCtrlRegs.PIEIER6.bit.INTx1 = 1;
IER |= M_INT6; // Enable group 9 interrupts
EDIS;
SpiaRegs.SPIFFTX.all = 0xC042; // Enable FIFOs, set TX FIFO level to 4
SpiaRegs.SPIFFRX.all = 0x4070; // Set RX FIFO level to 4
SpiaRegs.SPIFFCT.all = 0x00;
SpiaRegs.SPIFFRX.bit.RXFFIENA = 1;
// Initialize SPI-A
SpiaRegs.***.all = 0x0007;
SpiaRegs.***.all = 0x000E;
SpiaRegs.***.bit.SPIINTENA = 1;
SpiaRegs.***.bit.OVERRUNINTENA = 1;
// Set the baud rate
SpiaRegs.SPIBRR.bit.SPI_BIT_RATE = 0x7F;
// Set FREE bit
// Halting on a breakpoint will not halt the SPI
SpiaRegs.SPIPRI.bit.FREE = 1;
// Release the SPI from reset
SpiaRegs.***.bit.SPISWRESET = 1;
SpiaRegs.SPIFFTX.bit.TXFIFO=1;
SpiaRegs.SPIFFRX.bit.RXFIFORESET=1;
