Mike Moore
SPI library used to communicate with an altera development board attached to four zigbee-header pins.
mmSPI.cpp
- Committer:
- gatedClock
- Date:
- 2013-08-19
- Revision:
- 18:4a29cad91540
- Parent:
- 17:b81c0c1f312f
- Child:
- 19:c2b753533b93
File content as of revision 18:4a29cad91540:
/*----------------------------------------------//------------------------------
student : m-moore
class : external SPI interface
directory : mmSPI
file : mmSPI.cpp
------------------------------------------------//----------------------------*/
#include "mmSPI.h"
/*----------------------------------------------//------------------------------
------------------------------------------------//----------------------------*/
//==============================================//==============================
// consider resetting the fpga around here, because
// the micro may be wiggling these signals before here.
mmSPI::mmSPI() // constructor.
{
allocations(); // object allocations.
*pSCLK = 0; // initialize.
*pCPUclk = 0; // initialize.
}
//----------------------------------------------//------------------------------
mmSPI::~mmSPI() // destructor.
{
// deallocations.
if (pMOSI) {delete pMOSI; pMOSI = NULL;}
if (pMISO) {delete pMISO; pMISO = NULL;}
if (pSCLK) {delete pSCLK; pSCLK = NULL;}
if (pCPUclk) {delete pCPUclk; pCPUclk = NULL;}
}
//----------------------------------------------//------------------------------
void mmSPI::allocations(void) // object allocations.
{
pMOSI = new DigitalOut(mmSPI_MOSI); // SPI MOSI pin object.
if (!pMOSI) error("\n\r mmSPI::allocations : FATAL malloc error for pMOSI. \n\r");
pMISO = new DigitalOut(mmSPI_MISO); // SPI MISO pin object.
if (!pMISO) error("\n\r mmSPI::allocations : FATAL malloc error for pMISO. \n\r");
pSCLK = new DigitalOut(mmSPI_SCLK); // SPI SCLK pin object.
if (!pSCLK) error("\n\r mmSPI::allocations : FATAL malloc error for pSCLK. \n\r");
pCPUclk = new DigitalOut(mmCPU_CLK); // SPI SCLK pin object.
if (!pCPUclk) error("\n\r mmSPI::allocations : FATAL malloc error for pCPUclk. \n\r");
}
//----------------------------------------------//------------------------------
void mmSPI::setSPIfrequency(float fFreq) // set SPI clock frequency.
{
fSPIfreq = fFreq; // promote to object scope.
if (fSPIfreq < .05) // don't get near divide-by-zero.
error("\n\r mmSPI::setSPIfrequency : FATAL SPI frequency set too low. \n\r");
fSPIquarterP = (1 / fSPIfreq) / 4; // figure quarter-cycle period.
}
//----------------------------------------------//------------------------------
// we're not going for speed, so lets go for good setup / hold.
// send/receive a byte over SPI.
// MSB out/in first.
void mmSPI::transceive_byte(char *cReceive, char *cSend)
{
*cReceive = 0; // clear receive byte.
for (dLoop01 = 7; dLoop01 >= 0; dLoop01--)// loop for 8 bits in the byte.
{
*pSCLK = 0; // SPI clock negedge.
wait(fSPIquarterP); // until middle of clock low.
*pMOSI = (*cSend >> dLoop01) & 1; // assert MOSI.
// capture MISO.
*cReceive = *cReceive | (*pMISO << dLoop01);
wait(fSPIquarterP); // finish-out cycle.
*pSCLK = 1; // SPI clock posedge.
wait(fSPIquarterP); // finish-out cycle.
wait(fSPIquarterP); // finish-out cycle.
}
}
//----------------------------------------------//------------------------------
// transceive a character array.
// limit is 256 characters.
// MSB out/in first.
void mmSPI::transceive_vector(char *cReceive, char *cSend, char cNumBytes)
{
for (dLoop02 = (cNumBytes - 1); dLoop02 >= 0; dLoop02--)
transceive_byte(&(cReceive[dLoop02]), &(cSend[dLoop02]));
*pCPUclk = 1; // pulse the CPU clock.
wait(fSPIquarterP);
wait(fSPIquarterP);
*pCPUclk = 0;
wait(fSPIquarterP);
wait(fSPIquarterP);
if (0)
{
*pSCLK = 1;
wait(fSPIquarterP);
wait(fSPIquarterP);
*pSCLK = 0;
wait(fSPIquarterP);
wait(fSPIquarterP);
}
}
//----------------------------------------------//------------------------------
// transceive a character array.
// limit is 256 characters.
// MSB out/in first.
void mmSPI::transceive_vector2(char *pcReceive, char *pcSend, int dNumBytes)
{
int dClear;
int dIndex;
int dMosiByteIndex;
int dMosiBitIndex;
int dMisoByteIndex;
int dMisoBitIndex;
dIndex = (dNumBytes * 8) - 1;
dMosiByteIndex = dIndex / 8;
dMosiBitIndex = dIndex % 8;
for (dClear = 0; dClear < dNumBytes; dClear++) pcReceive[dClear] = 0;
*pCPUclk = 1; // pulse the CPU clock.
wait(fSPIquarterP);
wait(fSPIquarterP);
*pCPUclk = 0;
wait(fSPIquarterP);
wait(fSPIquarterP);
*pSCLK = 1; // pulse the SPI clock for parallel load.
wait(fSPIquarterP);
wait(fSPIquarterP);
*pSCLK = 0;
// pre-assert MOSI.
*pMOSI = ((pcSend[dMosiByteIndex]) >> dMosiBitIndex) & 1;
wait(fSPIquarterP);
wait(fSPIquarterP);
for (dIndex = (dNumBytes * 8) - 1; dIndex >= 0; dIndex--)
{
dMisoByteIndex = dIndex / 8;
dMisoBitIndex = dIndex % 8;
pcReceive[dMisoByteIndex] = pcReceive[dMisoByteIndex] | (*pMISO << dMisoBitIndex);
*pSCLK = 1;
wait(fSPIquarterP);
wait(fSPIquarterP);
*pSCLK = 0;
if (dIndex < 0) dIndex = 0;
dMosiByteIndex = (dIndex - 1) / 8;
dMosiBitIndex = (dIndex - 1) % 8;
*pMOSI = ((pcSend[dMosiByteIndex]) >> dMosiBitIndex) & 1;
wait(fSPIquarterP);
wait(fSPIquarterP);
}
}
//----------------------------------------------//------------------------------
// transceive a character array.
// limit is 256 characters.
// MSB out/in first.
void mmSPI::test_toggle_cpu_clock(void)
{
DigitalOut led0(LED4);
while (1)
{
*pCPUclk = 1; led0 = 1;
wait(1.0);
*pCPUclk = 0; led0 = 0;
wait(1.0);
}
}
//----------------------------------------------//------------------------------
void mmSPI::force_write(char cDataHIgh, char cDataLow, char cAddress)
{
char pcReceive[8];
char pcSend [8];
int dLoop;
for (dLoop = 0; dLoop < 8; dLoop++) pcSend[dLoop] = 0;
// high data to R2.
pcSend[7] = 0x02; pcSend[1] = 0xA8; pcSend[0] = cDataHIgh;
transceive_vector(pcReceive, pcSend, 8);
// low data to R1.
pcSend[7] = 0x02; pcSend[1] = 0xA4; pcSend[0] = cDataLow;
transceive_vector(pcReceive, pcSend, 8);
// address to R3.
pcSend[7] = 0x02; pcSend[1] = 0xAC; pcSend[0] = cAddress;
transceive_vector(pcReceive, pcSend, 8);
pcSend[7] = 0x02; pcSend[1] = 0x02; pcSend[0] = 0; // WE high.
transceive_vector(pcReceive, pcSend, 8);
pcSend[7] = 0x02; pcSend[1] = 0x00; pcSend[0] = 0; // WE low.
transceive_vector(pcReceive, pcSend, 8);
}
//----------------------------------------------//------------------------------
void mmSPI::force_read(char cAddress)
{
char pcReceive[8];
char pcSend [8];
int dLoop;
for (dLoop = 0; dLoop < 8; dLoop++) pcSend[dLoop] = 0;
// address to R3.
pcSend[7] = 0x02; pcSend[1] = 0xAC; pcSend[0] = cAddress;
transceive_vector(pcReceive, pcSend, 8);
// R2 gets data-H from memory.
pcSend[7] = 0x02; pcSend[1] = 0xC8; pcSend[0] = cAddress;
transceive_vector(pcReceive, pcSend, 8);
// R1 gets data-L from memory.
pcSend[7] = 0x02; pcSend[1] = 0xC4; pcSend[0] = cAddress;
transceive_vector(pcReceive, pcSend, 8);
// pcSend[7] = 0x02; // force IR.
// pcSend[1] = 0xA4; // R1 <- immediate.
// pcSend[0] = 0xEE; // immediate value.
/// transceive_vector(pcReceive, pcSend, 8);
// no-op scan.
pcSend[7] = 0x02; pcSend[1] = 0x0; pcSend[0] = 0;
transceive_vector(pcReceive, pcSend, 8);
}
//----------------------------------------------//------------------------------
void mmSPI::write_register(char cRegister, char cValue, char * pcReceive, char * pcSend)
{
int dLoop; // loop index.
// clear transmit vector.
for (dLoop = 0; dLoop < 8; dLoop++) pcSend[dLoop] = 0x00;
pcSend[7] = 0x02; // mbed sends a command.
// align into instruction word.
pcSend[1] = ((cRegister & 0x07) << 2) | 0xA0;
pcSend[0] = cValue & 0xFF; // immediate value to i.w.
transceive_vector2(pcReceive, pcSend, 8); // transmit command.
// clear transmit vector.
for (dLoop = 0; dLoop < 8; dLoop++) pcSend[dLoop] = 0x00;
}
//----------------------------------------------//------------------------------
// returns the content of
// a CPU register.
char mmSPI::read_register(char cRegister, char * pcReceive, char * pcSend)
{
int dLoop; // send all 0.
for (dLoop = 0; dLoop < 8; dLoop++) pcSend[dLoop] = 0x00;
transceive_vector2(pcReceive, pcSend, 8); // snap & scan-out reg contents.
return (pcReceive[cRegister]); // return the particular reg value.
}
//----------------------------------------------//------------------------------
void mmSPI::write_memory(char cHData, char cLdata, char cAddress, char * pcReceive, char * pcSend)
{
int dLoop; // loop index.
// clear transmit vector.
for (dLoop = 0; dLoop < 8; dLoop++) pcSend[dLoop] = 0x00;
// R3 <- address.
// R2 <- high-data.
// R1 <- low-data.
write_register(0x03,cAddress, pcReceive, pcSend);
write_register(0x02,cHData, pcReceive, pcSend);
write_register(0x01,cLdata, pcReceive, pcSend);
pcSend[7] = 0x02; // write-enable high.
pcSend[1] = 0x02;
pcSend[0] = 0x00;
transceive_vector2(pcReceive, pcSend, 8);
pcSend[7] = 0x02; // write-enable low.
pcSend[1] = 0x00;
pcSend[0] = 0x00;
transceive_vector2(pcReceive, pcSend, 8);
// clear transmit vector.
for (dLoop = 0; dLoop < 8; dLoop++) pcSend[dLoop] = 0x00;
}
//----------------------------------------------//------------------------------
// fetch a word from main memory.
unsigned int mmSPI::read_memory(char cAddress, char * pcReceive, char * pcSend)
{
int dLoop; // loop index.
unsigned int udMemoryContent; // return variable.
char cHData; // returned data-high.
char cLData; // returned data-low.
// clear transmit vector.
for (dLoop = 0; dLoop < 8; dLoop++) pcSend[dLoop] = 0x00;
// R3 <- address.
write_register(0x03,cAddress, pcReceive, pcSend);
pcSend[7] = 0x02; // mbed sends command.
pcSend[1] = 0x68; // R2 <- MM[R3]
pcSend[0] = 0x00;
transceive_vector2(pcReceive, pcSend, 8); // send command.
pcSend[7] = 0x02; // mbed sends command.
pcSend[1] = 0x64; // R1 <- MM[R3]
pcSend[0] = 0x00;
transceive_vector2(pcReceive, pcSend, 8); // send command.
// obtain MM content.
cHData = read_register(0x02, pcReceive, pcSend);
cLData = read_register(0x01, pcReceive, pcSend);
udMemoryContent = (cHData << 8) + cLData; // build the memory word.
// clear transmit vector.
for (dLoop = 0; dLoop < 8; dLoop++) pcSend[dLoop] = 0x00;
return udMemoryContent; // return the memory word.
}
//----------------------------------------------//------------------------------
void mmSPI::write_pulse(char * pcReceive, char * pcSend)
{
pcSend[7] = 0x02; // write-enable high.
pcSend[1] = 0x02;
pcSend[0] = 0x00;
transceive_vector2(pcReceive, pcSend, 8);
pcSend[7] = 0x02; // write-enable low.
pcSend[1] = 0x00;
pcSend[0] = 0x00;
transceive_vector2(pcReceive, pcSend, 8);
pcSend[7] = 0x00;
pcSend[6] = 0x00;
pcSend[5] = 0x00;
pcSend[4] = 0x00;
pcSend[3] = 0x00;
pcSend[2] = 0x00;
pcSend[1] = 0x00;
pcSend[0] = 0x00;
}
//----------------------------------------------//------------------------------