Mike Moore / mmSPI-2

This is an involuntary fork, created because the repository would not update mmSPI. SPI library used to communicate with an altera development board attached to four zigbee-header pins.

Dependents:   Embedded_RTOS_Project

Fork of mmSPI by Mike Moore

mmSPI.cpp@14:35717622a4fb, 2013-08-18 (annotated)

Committer:
gatedClock
Date:
Sun Aug 18 04:50:54 2013 +0000
Revision:
14:35717622a4fb
Parent:
13:3e6886a96aea
Child:
15:d6cc57c4e23d
AC immediate value is seen from R0 LED monitor.

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 0:fb42c5acf810 11 mmSPI::mmSPI() // constructor.
gatedClock 0:fb42c5acf810 12 {
gatedClock 3:de99451ab3c0 13 allocations(); // object allocations.
gatedClock 0:fb42c5acf810 14 }
gatedClock 0:fb42c5acf810 15 //----------------------------------------------//------------------------------
gatedClock 0:fb42c5acf810 16 mmSPI::~mmSPI() // destructor.
gatedClock 0:fb42c5acf810 17 {
gatedClock 8:e2d8bbc3e659 18 // deallocations.
gatedClock 8:e2d8bbc3e659 19 if (pMOSI) {delete pMOSI; pMOSI = NULL;}
gatedClock 8:e2d8bbc3e659 20 if (pMISO) {delete pMISO; pMISO = NULL;}
gatedClock 8:e2d8bbc3e659 21 if (pSCLK) {delete pSCLK; pSCLK = NULL;}
gatedClock 8:e2d8bbc3e659 22 if (pCPUclk) {delete pCPUclk; pCPUclk = NULL;}
gatedClock 3:de99451ab3c0 23 }
gatedClock 3:de99451ab3c0 24 //----------------------------------------------//------------------------------
gatedClock 3:de99451ab3c0 25 void mmSPI::allocations(void) // object allocations.
gatedClock 3:de99451ab3c0 26 {
gatedClock 8:e2d8bbc3e659 27 pMOSI = new DigitalOut(mmSPI_MOSI); // SPI MOSI pin object.
gatedClock 3:de99451ab3c0 28 if (!pMOSI) error("\n\r mmSPI::allocations : FATAL malloc error for pMOSI. \n\r");
gatedClock 3:de99451ab3c0 29
gatedClock 8:e2d8bbc3e659 30 pMISO = new DigitalOut(mmSPI_MISO); // SPI MISO pin object.
gatedClock 3:de99451ab3c0 31 if (!pMISO) error("\n\r mmSPI::allocations : FATAL malloc error for pMISO. \n\r");
gatedClock 3:de99451ab3c0 32
gatedClock 8:e2d8bbc3e659 33 pSCLK = new DigitalOut(mmSPI_SCLK); // SPI SCLK pin object.
gatedClock 3:de99451ab3c0 34 if (!pSCLK) error("\n\r mmSPI::allocations : FATAL malloc error for pSCLK. \n\r");
gatedClock 8:e2d8bbc3e659 35
gatedClock 8:e2d8bbc3e659 36 pCPUclk = new DigitalOut(mmCPU_CLK); // SPI SCLK pin object.
gatedClock 8:e2d8bbc3e659 37 if (!pCPUclk) error("\n\r mmSPI::allocations : FATAL malloc error for pCPUclk. \n\r");
gatedClock 3:de99451ab3c0 38 }
gatedClock 4:aa1fe8707bef 39 //----------------------------------------------//------------------------------
gatedClock 4:aa1fe8707bef 40 void mmSPI::setSPIfrequency(float fFreq) // set SPI clock frequency.
gatedClock 4:aa1fe8707bef 41 {
gatedClock 4:aa1fe8707bef 42 fSPIfreq = fFreq; // promote to object scope.
gatedClock 4:aa1fe8707bef 43 if (fSPIfreq < .05) // don't get near divide-by-zero.
gatedClock 4:aa1fe8707bef 44 error("\n\r mmSPI::setSPIfrequency : FATAL SPI frequency set too low. \n\r");
gatedClock 4:aa1fe8707bef 45 fSPIquarterP = (1 / fSPIfreq) / 4; // figure quarter-cycle period.
gatedClock 4:aa1fe8707bef 46 }
gatedClock 0:fb42c5acf810 47 //----------------------------------------------//------------------------------
gatedClock 5:b14dcaae260e 48 // we're not going for speed, so lets go for good setup / hold.
gatedClock 6:b480fc4e87e5 49
gatedClock 6:b480fc4e87e5 50 // send/receive a byte over SPI.
gatedClock 7:b3e8b537d5c2 51 // MSB out/in first.
gatedClock 6:b480fc4e87e5 52 void mmSPI::transceive_byte(char *cReceive, char *cSend)
gatedClock 1:15706d15d123 53 {
gatedClock 6:b480fc4e87e5 54 *cReceive = 0; // clear receive byte.
gatedClock 12:a1b7ce9c1d64 55 for (dLoop01 = 7; dLoop01 >= 0; dLoop01--)// loop for 8 bits in the byte.
gatedClock 5:b14dcaae260e 56 {
gatedClock 5:b14dcaae260e 57 *pSCLK = 0; // SPI clock negedge.
gatedClock 5:b14dcaae260e 58 wait(fSPIquarterP); // until middle of clock low.
gatedClock 12:a1b7ce9c1d64 59 *pMOSI = (*cSend >> dLoop01) & 1; // assert MOSI.
gatedClock 5:b14dcaae260e 60 wait(fSPIquarterP); // MOSI setup time
gatedClock 5:b14dcaae260e 61 *pSCLK = 1; // SPI clock posedge.
gatedClock 5:b14dcaae260e 62 wait(fSPIquarterP); // MISO setup time.
gatedClock 12:a1b7ce9c1d64 63 *cReceive = *cReceive | (*pMISO << dLoop01);
gatedClock 5:b14dcaae260e 64 wait(fSPIquarterP); // finish-out cycle.
gatedClock 5:b14dcaae260e 65 }
gatedClock 1:15706d15d123 66 }
gatedClock 5:b14dcaae260e 67 //----------------------------------------------//------------------------------
gatedClock 7:b3e8b537d5c2 68 // transceive a character array.
gatedClock 7:b3e8b537d5c2 69 // limit is 256 characters.
gatedClock 7:b3e8b537d5c2 70 // MSB out/in first.
gatedClock 7:b3e8b537d5c2 71 void mmSPI::transceive_vector(char *cReceive, char *cSend, char cNumBytes)
gatedClock 13:3e6886a96aea 72 {
gatedClock 13:3e6886a96aea 73 // the first SPI pulse after the
gatedClock 13:3e6886a96aea 74 // CPU clock goes low is used for
gatedClock 13:3e6886a96aea 75 // parallel-load of the SPI shadow
gatedClock 13:3e6886a96aea 76 // registers, not for shifting.
gatedClock 13:3e6886a96aea 77 if (0)
gatedClock 13:3e6886a96aea 78 {
gatedClock 13:3e6886a96aea 79 *pSCLK = 1;
gatedClock 13:3e6886a96aea 80 wait(fSPIquarterP);
gatedClock 13:3e6886a96aea 81 wait(fSPIquarterP);
gatedClock 13:3e6886a96aea 82 *pSCLK = 0;
gatedClock 13:3e6886a96aea 83 wait(fSPIquarterP);
gatedClock 13:3e6886a96aea 84 wait(fSPIquarterP);
gatedClock 13:3e6886a96aea 85 }
gatedClock 13:3e6886a96aea 86
gatedClock 12:a1b7ce9c1d64 87 for (dLoop02 = (cNumBytes - 1); dLoop02 >= 0; dLoop02--)
gatedClock 12:a1b7ce9c1d64 88 transceive_byte(&(cReceive[dLoop02]), &(cSend[dLoop02]));
gatedClock 13:3e6886a96aea 89
gatedClock 13:3e6886a96aea 90 *pSCLK = 0; // SPI clock rests low.
gatedClock 13:3e6886a96aea 91
gatedClock 13:3e6886a96aea 92 *pCPUclk = 1; // pulse the CPU clock.
gatedClock 13:3e6886a96aea 93 wait(fSPIquarterP);
gatedClock 13:3e6886a96aea 94 wait(fSPIquarterP);
gatedClock 13:3e6886a96aea 95 *pCPUclk = 0;
gatedClock 13:3e6886a96aea 96 wait(fSPIquarterP);
gatedClock 13:3e6886a96aea 97 wait(fSPIquarterP);
gatedClock 7:b3e8b537d5c2 98 }
gatedClock 7:b3e8b537d5c2 99 //----------------------------------------------//------------------------------
gatedClock 9:0551307e3b15 100 // transceive a character array.
gatedClock 9:0551307e3b15 101 // limit is 256 characters.
gatedClock 9:0551307e3b15 102 // MSB out/in first.
gatedClock 9:0551307e3b15 103 void mmSPI::test_toggle_cpu_clock(void)
gatedClock 9:0551307e3b15 104 {
gatedClock 11:17207edac925 105 DigitalOut led0(LED4);
gatedClock 9:0551307e3b15 106 while (1)
gatedClock 9:0551307e3b15 107 {
gatedClock 11:17207edac925 108 *pCPUclk = 1; led0 = 1;
gatedClock 9:0551307e3b15 109 wait(1.0);
gatedClock 11:17207edac925 110 *pCPUclk = 0; led0 = 0;
gatedClock 9:0551307e3b15 111 wait(1.0);
gatedClock 9:0551307e3b15 112 }
gatedClock 9:0551307e3b15 113 }
gatedClock 9:0551307e3b15 114 //----------------------------------------------//------------------------------
gatedClock 5:b14dcaae260e 115
gatedClock 5:b14dcaae260e 116
gatedClock 14:35717622a4fb 117
gatedClock 14:35717622a4fb 118
gatedClock 14:35717622a4fb 119
gatedClock 14:35717622a4fb 120
gatedClock 14:35717622a4fb 121
gatedClock 14:35717622a4fb 122
gatedClock 14:35717622a4fb 123
gatedClock 14:35717622a4fb 124 //----------------------------------------------//------------------------------
gatedClock 5:b14dcaae260e 125
gatedClock 5:b14dcaae260e 126
gatedClock 5:b14dcaae260e 127
gatedClock 5:b14dcaae260e 128
gatedClock 5:b14dcaae260e 129
gatedClock 5:b14dcaae260e 130
gatedClock 5:b14dcaae260e 131
gatedClock 7:b3e8b537d5c2 132
gatedClock 7:b3e8b537d5c2 133
gatedClock 7:b3e8b537d5c2 134
gatedClock 7:b3e8b537d5c2 135
gatedClock 7:b3e8b537d5c2 136