Solved
SPI configuration - Send & Receive
Posted on April 21, 2017 at 21:39
Hi, I am trying to configure the SPI moduleon the
SPC570S40E1 microcontroller to communicate with an external device.
The devicerequiresmessage length of 40 bits.I would like to know if I am setting up the function for exchanging data correctly. The issue I am seeing currently is right after pushing theset of frames( 16,16, 8 bits) to transfer the second message,the EOQFand the TXRXs bits in the status registers remain set even after clearing the EOQF bit. You can see the the second time I am calling the Transmit_DSPI0 in the DSPI_0_Exchange function in the code below.
Here is the source code.
// SPI driver
#include 'SPI.h'
#include 'STM.h'
void Initialize_DSPI0(void)
{
// Configure DSPI0 Module Configuration Register ( DSPI0_MCR )
// MSTR - 1 , Master mode
// CONT_SCKE - 0 , Continuous SCK disabled
// DCONF - 00 , SPI
// FRZ - 0 , Do not halt serial transfers in debug mode
// MTFE - 0 , Modified Timing Format disabled
// ROOE - 0 , (Receive FIFO Overflow Overwrite) Incoming data is ignored
// PCSIS0 - 1 , Inactive state of PCS0 is high
// MDIS - 1 , Allow external logic to disable DSPI clocks
// DIS_TXF - 0 , TX FIFO enabled
// DIS_RXF - 0 , RX FIFO enabled
// XSPI - 0 , Normal SPI Mode
// FCPCS - 1 , Fast Continuous PCS mode.
// PES - 0 , SPI frame transmission continues
// HALT - 0 , Start transfers
DSPI_0.MCR.R = 0x80010004;
// Configure CTAR0 and CTAR1 ( Clock and Transfer Attributes ) Register
// Two transfer attributes used. CTAR0 configured for 16-bit frame size. CTAR1 configured for 8-bit frame size.
// DBR - 0 , Baud rate not doubled
// FMSZ(for CTAR0) - 1111 , Frame size set to FMSZ + 1 or 16 bits
// CPOL - 0 , Clock Polarity - Inactive state value of SCK is low
// CPHA - 0 , Data is captured on the leading edge of SCK and changed on the following edge
// LSBFE - 0 , MSB is transferred first
// PCSSCK - 00 , PCS to SCK Prescaler value is 1
// PASC - 00 , Sets the delay between last SCK edge to negation of CS, 00 sets the Prescaler value to 1
// PDT - 00 , Sets the delay between negation of PCS at end of frame to assertion beginning of next frame, 00 - Prescaler set to 1
// PBR - 00 , Baud Rate Prescaler, set to 2. Available values - 2,3,5, and 7
// CSSCK - 0000 , PCS to SCK Delay Scaler set to 2
// ASC - 0000 , Scaler value for the After SCK Delay, set to 2
// DT - 0000 , Scaler value set to 2
// BR - 0011 , Baud Rate scaler set to 8
/* ------------ Calculation ------------------------
SPI Baud Rate = (Fp / PBR) * ( [1 + DBR]/BR ) , Fp = Peripheral Clock / AC0_DC3 = 64/1 = 64Mhz
= (64/2) * ( [1]/8 )
= 64/16
= 4Mhz
*/
DSPI_0.CTAR[0].R = 0x78000003;
DSPI_0.CTAR[1].R = 0x38000003;
}
void Transmit_DSPI0(uint8_t Tx_Frame[])
{
// Clear transmit FIFO
DSPI_0.MCR.B.CLR_TXF = 1;
DSPI_0.PUSHR.R = CONT_Enable | CTAS(0) | EOQ_Not_Last_Data | Clear_Transfer_Counter | PCS0 | TX_Data(((Tx_Frame[0]<<8)|Tx_Frame[1]));
DSPI_0.PUSHR.R = CONT_Enable | CTAS(0) | EOQ_Not_Last_Data | PCS0 | TX_Data(((Tx_Frame[2]<<8)|Tx_Frame[3]));
DSPI_0.PUSHR.R = CONT_Disable | CTAS(1) | EOQ_Last_Data | PCS0 | TX_Data(Tx_Frame[4]);
// Wait until all three frames have been transmitted.
while (DSPI_0.TCR.B.SPI_TCNT != 3 )
{
}
//Clear the EOQF bit
DSPI_0.SR.R = EOQF;
//wait for the End of Queue flag bit to reset.
while((DSPI_0.SR.R & EOQF) != 0)
{
}
}
void DSPI_0_Exchange(uint8_t Tx_Frame[])
{
uint8_t Dummy_Message[5] = {0,0,0,0,0};
// Send the valid frame
Transmit_DSPI0(Tx_Frame);
DSPI_0.POPR;
DSPI_0.POPR;
DSPI_0.POPR;
DSPI_0.SR.R = RFDF;
// Delay 1ms
Delay_Microseconds(1000);
// Send a dummy frame to get the response frame
Transmit_DSPI0(Dummy_Message);
DSPI_0.POPR;
DSPI_0.POPR;
DSPI_0.POPR;
DSPI_0.SR.R = RFDF;
}
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