Mike Moore / mmSPI

SPI library used to communicate with an altera development board attached to four zigbee-header pins.

mmSPI.cpp@29:4ed71dfee7d8, 2013-08-25 (annotated)

Committer:
gatedClock
Date:
Sun Aug 25 06:05:30 2013 +0000
Revision:
29:4ed71dfee7d8
Parent:
27:fb63c8b70bc2
Child:
30:331c7c7d8bc1
instead, try suppressing cpu operation during register read.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
gatedClock 0:fb42c5acf810 1 /*----------------------------------------------//------------------------------
gatedClock 0:fb42c5acf810 2 student : m-moore
gatedClock 0:fb42c5acf810 3 class : external SPI interface
gatedClock 0:fb42c5acf810 4 directory : mmSPI
gatedClock 0:fb42c5acf810 5 file : mmSPI.cpp
gatedClock 0:fb42c5acf810 6 ------------------------------------------------//----------------------------*/
gatedClock 0:fb42c5acf810 7 #include "mmSPI.h"
gatedClock 0:fb42c5acf810 8 /*----------------------------------------------//------------------------------
gatedClock 0:fb42c5acf810 9 ------------------------------------------------//----------------------------*/
gatedClock 0:fb42c5acf810 10 //==============================================//==============================
gatedClock 15:d6cc57c4e23d 11 // consider resetting the fpga around here, because
gatedClock 15:d6cc57c4e23d 12 // the micro may be wiggling these signals before here.
gatedClock 0:fb42c5acf810 13 mmSPI::mmSPI() // constructor.
gatedClock 0:fb42c5acf810 14 {
gatedClock 3:de99451ab3c0 15 allocations(); // object allocations.
gatedClock 15:d6cc57c4e23d 16
gatedClock 15:d6cc57c4e23d 17 *pSCLK = 0; // initialize.
gatedClock 15:d6cc57c4e23d 18 *pCPUclk = 0; // initialize.
gatedClock 0:fb42c5acf810 19 }
gatedClock 0:fb42c5acf810 20 //----------------------------------------------//------------------------------
gatedClock 0:fb42c5acf810 21 mmSPI::~mmSPI() // destructor.
gatedClock 0:fb42c5acf810 22 {
gatedClock 8:e2d8bbc3e659 23 // deallocations.
gatedClock 8:e2d8bbc3e659 24 if (pMOSI) {delete pMOSI; pMOSI = NULL;}
gatedClock 8:e2d8bbc3e659 25 if (pMISO) {delete pMISO; pMISO = NULL;}
gatedClock 8:e2d8bbc3e659 26 if (pSCLK) {delete pSCLK; pSCLK = NULL;}
gatedClock 8:e2d8bbc3e659 27 if (pCPUclk) {delete pCPUclk; pCPUclk = NULL;}
gatedClock 3:de99451ab3c0 28 }
gatedClock 3:de99451ab3c0 29 //----------------------------------------------//------------------------------
gatedClock 3:de99451ab3c0 30 void mmSPI::allocations(void) // object allocations.
gatedClock 3:de99451ab3c0 31 {
gatedClock 8:e2d8bbc3e659 32 pMOSI = new DigitalOut(mmSPI_MOSI); // SPI MOSI pin object.
gatedClock 3:de99451ab3c0 33 if (!pMOSI) error("\n\r mmSPI::allocations : FATAL malloc error for pMOSI. \n\r");
gatedClock 3:de99451ab3c0 34
gatedClock 8:e2d8bbc3e659 35 pMISO = new DigitalOut(mmSPI_MISO); // SPI MISO pin object.
gatedClock 3:de99451ab3c0 36 if (!pMISO) error("\n\r mmSPI::allocations : FATAL malloc error for pMISO. \n\r");
gatedClock 3:de99451ab3c0 37
gatedClock 8:e2d8bbc3e659 38 pSCLK = new DigitalOut(mmSPI_SCLK); // SPI SCLK pin object.
gatedClock 3:de99451ab3c0 39 if (!pSCLK) error("\n\r mmSPI::allocations : FATAL malloc error for pSCLK. \n\r");
gatedClock 8:e2d8bbc3e659 40
gatedClock 8:e2d8bbc3e659 41 pCPUclk = new DigitalOut(mmCPU_CLK); // SPI SCLK pin object.
gatedClock 8:e2d8bbc3e659 42 if (!pCPUclk) error("\n\r mmSPI::allocations : FATAL malloc error for pCPUclk. \n\r");
gatedClock 3:de99451ab3c0 43 }
gatedClock 4:aa1fe8707bef 44 //----------------------------------------------//------------------------------
gatedClock 4:aa1fe8707bef 45 void mmSPI::setSPIfrequency(float fFreq) // set SPI clock frequency.
gatedClock 4:aa1fe8707bef 46 {
gatedClock 4:aa1fe8707bef 47 fSPIfreq = fFreq; // promote to object scope.
gatedClock 4:aa1fe8707bef 48 if (fSPIfreq < .05) // don't get near divide-by-zero.
gatedClock 4:aa1fe8707bef 49 error("\n\r mmSPI::setSPIfrequency : FATAL SPI frequency set too low. \n\r");
gatedClock 4:aa1fe8707bef 50 fSPIquarterP = (1 / fSPIfreq) / 4; // figure quarter-cycle period.
gatedClock 4:aa1fe8707bef 51 }
gatedClock 22:7524dee5c753 52 //----------------------------------------------//------------------------------
gatedClock 22:7524dee5c753 53 // obtain SPI send buffer pointer.
gatedClock 22:7524dee5c753 54 void mmSPI::setSendBuffer(char * pcSendBuffer)
gatedClock 22:7524dee5c753 55 {
gatedClock 22:7524dee5c753 56 pcSend = pcSendBuffer; // promote to object scope.
gatedClock 22:7524dee5c753 57 }
gatedClock 22:7524dee5c753 58 //----------------------------------------------//------------------------------
gatedClock 22:7524dee5c753 59 // obtain SPI receive buffer pointer.
gatedClock 22:7524dee5c753 60 void mmSPI::setReceiveBuffer(char * pcReceiveBuffer)
gatedClock 22:7524dee5c753 61 {
gatedClock 22:7524dee5c753 62 pcReceive = pcReceiveBuffer; // promote to object scope.
gatedClock 22:7524dee5c753 63 }
gatedClock 0:fb42c5acf810 64 //----------------------------------------------//------------------------------
gatedClock 22:7524dee5c753 65 // obtain number of SPI bytes.
gatedClock 22:7524dee5c753 66 void mmSPI::setNumberOfBytes(int dNumberOfBytes)
gatedClock 22:7524dee5c753 67 {
gatedClock 22:7524dee5c753 68 dNumBytes = dNumberOfBytes; // promote to object scope.
gatedClock 22:7524dee5c753 69 }
gatedClock 22:7524dee5c753 70 //----------------------------------------------//------------------------------
gatedClock 16:0e422fd263c6 71 // transceive a character array.
gatedClock 16:0e422fd263c6 72 // MSB out/in first.
gatedClock 23:dbd89a56716d 73 void mmSPI::transceive_vector(void)
gatedClock 16:0e422fd263c6 74 {
gatedClock 16:0e422fd263c6 75 int dClear;
gatedClock 16:0e422fd263c6 76 int dIndex;
gatedClock 16:0e422fd263c6 77 int dMosiByteIndex;
gatedClock 16:0e422fd263c6 78 int dMosiBitIndex;
gatedClock 16:0e422fd263c6 79 int dMisoByteIndex;
gatedClock 16:0e422fd263c6 80 int dMisoBitIndex;
gatedClock 16:0e422fd263c6 81
gatedClock 16:0e422fd263c6 82 dIndex = (dNumBytes * 8) - 1;
gatedClock 16:0e422fd263c6 83 dMosiByteIndex = dIndex / 8;
gatedClock 16:0e422fd263c6 84 dMosiBitIndex = dIndex % 8;
gatedClock 16:0e422fd263c6 85
gatedClock 16:0e422fd263c6 86 for (dClear = 0; dClear < dNumBytes; dClear++) pcReceive[dClear] = 0;
gatedClock 16:0e422fd263c6 87
gatedClock 16:0e422fd263c6 88
gatedClock 16:0e422fd263c6 89 *pCPUclk = 1; // pulse the CPU clock.
gatedClock 16:0e422fd263c6 90 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 91 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 92 *pCPUclk = 0;
gatedClock 16:0e422fd263c6 93 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 94 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 95
gatedClock 16:0e422fd263c6 96 *pSCLK = 1; // pulse the SPI clock for parallel load.
gatedClock 16:0e422fd263c6 97 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 98 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 99 *pSCLK = 0;
gatedClock 16:0e422fd263c6 100 // pre-assert MOSI.
gatedClock 16:0e422fd263c6 101 *pMOSI = ((pcSend[dMosiByteIndex]) >> dMosiBitIndex) & 1;
gatedClock 16:0e422fd263c6 102 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 103 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 104
gatedClock 16:0e422fd263c6 105
gatedClock 16:0e422fd263c6 106 for (dIndex = (dNumBytes * 8) - 1; dIndex >= 0; dIndex--)
gatedClock 16:0e422fd263c6 107 {
gatedClock 16:0e422fd263c6 108 dMisoByteIndex = dIndex / 8;
gatedClock 16:0e422fd263c6 109 dMisoBitIndex = dIndex % 8;
gatedClock 18:4a29cad91540 110 pcReceive[dMisoByteIndex] = pcReceive[dMisoByteIndex] | (*pMISO << dMisoBitIndex);
gatedClock 16:0e422fd263c6 111 *pSCLK = 1;
gatedClock 16:0e422fd263c6 112 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 113 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 114 *pSCLK = 0;
gatedClock 16:0e422fd263c6 115
gatedClock 16:0e422fd263c6 116 if (dIndex < 0) dIndex = 0;
gatedClock 16:0e422fd263c6 117 dMosiByteIndex = (dIndex - 1) / 8;
gatedClock 16:0e422fd263c6 118 dMosiBitIndex = (dIndex - 1) % 8;
gatedClock 16:0e422fd263c6 119 *pMOSI = ((pcSend[dMosiByteIndex]) >> dMosiBitIndex) & 1;
gatedClock 16:0e422fd263c6 120 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 121 wait(fSPIquarterP);
gatedClock 16:0e422fd263c6 122 }
gatedClock 7:b3e8b537d5c2 123 }
gatedClock 7:b3e8b537d5c2 124 //----------------------------------------------//------------------------------
gatedClock 26:26a8f31a31b8 125 // cRegister -> CPU_register
gatedClock 26:26a8f31a31b8 126 // 0 R0
gatedClock 26:26a8f31a31b8 127 // 1 R1
gatedClock 26:26a8f31a31b8 128 // 2 R2
gatedClock 26:26a8f31a31b8 129 // 3 R3
gatedClock 26:26a8f31a31b8 130 // 4 PC
gatedClock 26:26a8f31a31b8 131 // 5 <meta, don't do>
gatedClock 26:26a8f31a31b8 132 // 6 <nothing>
gatedClock 26:26a8f31a31b8 133 // 7 <nothing>
gatedClock 26:26a8f31a31b8 134
gatedClock 23:dbd89a56716d 135 void mmSPI::write_register(char cRegister, char cValue)
gatedClock 16:0e422fd263c6 136 {
gatedClock 18:4a29cad91540 137 int dLoop; // loop index.
gatedClock 18:4a29cad91540 138
gatedClock 24:d3b8c68f41f2 139 clear_transmit_vector(); // clear transmit vector.
gatedClock 18:4a29cad91540 140
gatedClock 18:4a29cad91540 141 pcSend[7] = 0x02; // mbed sends a command.
gatedClock 18:4a29cad91540 142
gatedClock 18:4a29cad91540 143 // align into instruction word.
gatedClock 16:0e422fd263c6 144 pcSend[1] = ((cRegister & 0x07) << 2) | 0xA0;
gatedClock 18:4a29cad91540 145 pcSend[0] = cValue & 0xFF; // immediate value to i.w.
gatedClock 17:b81c0c1f312f 146
gatedClock 23:dbd89a56716d 147 transceive_vector(); // transmit command.
gatedClock 18:4a29cad91540 148
gatedClock 24:d3b8c68f41f2 149 clear_transmit_vector(); // clear transmit vector.
gatedClock 17:b81c0c1f312f 150 }
gatedClock 17:b81c0c1f312f 151 //----------------------------------------------//------------------------------
gatedClock 26:26a8f31a31b8 152 // cRegister -> CPU_register
gatedClock 26:26a8f31a31b8 153 // 0 -> R0
gatedClock 26:26a8f31a31b8 154 // 1 -> R1
gatedClock 26:26a8f31a31b8 155 // 2 -> R2
gatedClock 26:26a8f31a31b8 156 // 3 -> R3
gatedClock 26:26a8f31a31b8 157 // 4 -> PC
gatedClock 26:26a8f31a31b8 158 // 5 -> IR-H
gatedClock 26:26a8f31a31b8 159 // 6 -> IR-L
gatedClock 26:26a8f31a31b8 160 // 7 -> <never-use>
gatedClock 17:b81c0c1f312f 161 // returns the content of
gatedClock 17:b81c0c1f312f 162 // a CPU register.
gatedClock 23:dbd89a56716d 163 char mmSPI::read_register(char cRegister)
gatedClock 17:b81c0c1f312f 164 {
gatedClock 24:d3b8c68f41f2 165 clear_transmit_vector(); // clear transmit vector.
gatedClock 29:4ed71dfee7d8 166
gatedClock 29:4ed71dfee7d8 167 pcSend[7] = 0x02; // suppress cpu operation.
gatedClock 29:4ed71dfee7d8 168
gatedClock 23:dbd89a56716d 169 transceive_vector(); // snap & scan-out reg contents.
gatedClock 17:b81c0c1f312f 170
gatedClock 19:c2b753533b93 171 return (pcReceive[6 - cRegister]); // return the particular reg value.
gatedClock 17:b81c0c1f312f 172 }
gatedClock 17:b81c0c1f312f 173 //----------------------------------------------//------------------------------
gatedClock 23:dbd89a56716d 174 void mmSPI::write_memory(char cHData, char cLdata, char cAddress)
gatedClock 18:4a29cad91540 175 {
gatedClock 24:d3b8c68f41f2 176 clear_transmit_vector(); // clear transmit vector.
gatedClock 24:d3b8c68f41f2 177
gatedClock 24:d3b8c68f41f2 178 write_register(0x03,cAddress); // R3 <- address.
gatedClock 24:d3b8c68f41f2 179 write_register(0x02,cHData); // R2 <- high-data.
gatedClock 24:d3b8c68f41f2 180 write_register(0x01,cLdata); // R1 <- low-data.
gatedClock 18:4a29cad91540 181
gatedClock 27:fb63c8b70bc2 182 pcSend[7] = 0x02; // mbed sends command.
gatedClock 27:fb63c8b70bc2 183 pcSend[1] = 0x02; // write-enable high.
gatedClock 27:fb63c8b70bc2 184 pcSend[0] = 0x00; // remainder of instruction.
gatedClock 23:dbd89a56716d 185 transceive_vector();
gatedClock 18:4a29cad91540 186
gatedClock 27:fb63c8b70bc2 187 pcSend[7] = 0x02; // mbed sends command.
gatedClock 27:fb63c8b70bc2 188 pcSend[1] = 0x00; // write-enable low.
gatedClock 27:fb63c8b70bc2 189 pcSend[0] = 0x00; // remainder of instruction.
gatedClock 23:dbd89a56716d 190 transceive_vector();
gatedClock 24:d3b8c68f41f2 191
gatedClock 24:d3b8c68f41f2 192 clear_transmit_vector(); // clear transmit vector.
gatedClock 18:4a29cad91540 193 }
gatedClock 18:4a29cad91540 194 //----------------------------------------------//------------------------------
gatedClock 18:4a29cad91540 195 // fetch a word from main memory.
gatedClock 23:dbd89a56716d 196 unsigned int mmSPI::read_memory(char cAddress)
gatedClock 24:d3b8c68f41f2 197 {
gatedClock 18:4a29cad91540 198 unsigned int udMemoryContent; // return variable.
gatedClock 18:4a29cad91540 199 char cHData; // returned data-high.
gatedClock 18:4a29cad91540 200 char cLData; // returned data-low.
gatedClock 24:d3b8c68f41f2 201
gatedClock 24:d3b8c68f41f2 202 clear_transmit_vector(); // clear transmit vector.
gatedClock 21:e90dd0f8aaa1 203
gatedClock 24:d3b8c68f41f2 204 write_register(0x03,cAddress); // R3 <= address.
gatedClock 18:4a29cad91540 205
gatedClock 18:4a29cad91540 206 pcSend[7] = 0x02; // mbed sends command.
gatedClock 20:2d5cd38047ca 207 pcSend[1] = 0xC8; // R2 <- MM[R3]
gatedClock 18:4a29cad91540 208 pcSend[0] = 0x00;
gatedClock 23:dbd89a56716d 209 transceive_vector(); // send command.
gatedClock 18:4a29cad91540 210
gatedClock 18:4a29cad91540 211 pcSend[7] = 0x02; // mbed sends command.
gatedClock 20:2d5cd38047ca 212 pcSend[1] = 0xC4; // R1 <- MM[R3]
gatedClock 18:4a29cad91540 213 pcSend[0] = 0x00;
gatedClock 23:dbd89a56716d 214 transceive_vector(); // send command.
gatedClock 18:4a29cad91540 215
gatedClock 24:d3b8c68f41f2 216 cHData = read_register(0x02); // obtain MM high-data-byte.
gatedClock 24:d3b8c68f41f2 217 cLData = read_register(0x01); // obtain MM low-data-byte.
gatedClock 18:4a29cad91540 218
gatedClock 18:4a29cad91540 219
gatedClock 18:4a29cad91540 220 udMemoryContent = (cHData << 8) + cLData; // build the memory word.
gatedClock 24:d3b8c68f41f2 221
gatedClock 24:d3b8c68f41f2 222 clear_transmit_vector(); // clear transmit vector.
gatedClock 18:4a29cad91540 223
gatedClock 18:4a29cad91540 224 return udMemoryContent; // return the memory word.
gatedClock 18:4a29cad91540 225 }
gatedClock 18:4a29cad91540 226 //----------------------------------------------//------------------------------
gatedClock 24:d3b8c68f41f2 227 void mmSPI::clear_transmit_vector(void) // fill transmit buffer with 0.
gatedClock 24:d3b8c68f41f2 228 {
gatedClock 24:d3b8c68f41f2 229 int dLoop;
gatedClock 24:d3b8c68f41f2 230 for (dLoop = 0; dLoop < dNumBytes; dLoop++) pcSend[dLoop] = 0x00;
gatedClock 24:d3b8c68f41f2 231 }
gatedClock 24:d3b8c68f41f2 232 //----------------------------------------------//------------------------------
gatedClock 17:b81c0c1f312f 233
gatedClock 17:b81c0c1f312f 234
gatedClock 5:b14dcaae260e 235
gatedClock 5:b14dcaae260e 236
gatedClock 5:b14dcaae260e 237
gatedClock 5:b14dcaae260e 238
gatedClock 5:b14dcaae260e 239
gatedClock 5:b14dcaae260e 240
gatedClock 5:b14dcaae260e 241
gatedClock 7:b3e8b537d5c2 242
gatedClock 7:b3e8b537d5c2 243
gatedClock 7:b3e8b537d5c2 244
gatedClock 7:b3e8b537d5c2 245