Configuration of SPI
The LCD can receive serial data via SPI interface, but this has to be first configured :// SPI Config SpiaRegs.SPICCR.all =0x0047; // Reset on, (clk pol=1 : Falling edge), 8-bit char bits SpiaRegs.SPICTL.all =0x0006; // Enable master mode, phase (without delay), enable talk, and SPI int disabled. SpiaRegs.SPIBRR =19; // 150 MHz/4/(19+1)= 1.97 MHz SpiaRegs.SPICCR.all =0x00C7; // Relinquish SPI from Reset SpiaRegs.SPIPRI.bit.FREE = 1; // Set so breakpoints dont disturb xmission |
Then you must :
- Initialise the LCD screen
- Send the data, periodically if you want to display variables changes or so...
LCD driver initialisation sequence
We must clear the LCD screen and configure correctly//---------------------------------------------------- // initialisation de l'écran LCD //---------------------------------------------------- inline void LCD_initScreen() { DispLCDOrder( 0xC0, 0x00); // foncé DelayNmSec(2); DispLCDOrder( 0x00, 0x80); // clear LCD, 1.53 ms DelayNmSec(2); DispLCDOrder( 0x00, 0x60); // increment, 1.53 ms DelayNmSec(2); DispLCDOrder( 0x00, 0x30); // display on, cursor Off DelayNmSec(1); //debug // DispLCDChar( 0x20, 0x80); // A // DelayNmSec(1); // DispLCDChar( 0x20, 0x40); // B // DelayNmSec(1); LCDupdate=1; // doit MAJ la table sur l Ecran LCD LCDcol=0; } |
Communication diagram
We must send 3 bytes on the SPI in the following sequence.
DispLCD function description
We have 2 inline functions to sends 3 bytes on the SPI.DispLCDChar sends characters corresponding to the Char Table (see below).
DispLCDOrder sends orders like configuration modification (clear screen, cursor home...).
//---------------------------------------------------- // Envoi 3 bytes pour Afficher : ordre requiert hi et low //---------------------------------------------------- inline void DispLCDChar(int hi, int low) { // debug : voir si on peut utiliser le fifo pour alleger le cpu LCD_CS=0; // Active le LCD via le /CS // SpiaRegs.SPIRXBUF=SpiaRegs.SPIRXBUF; // clear le SPISTS,BIT6 SpiaRegs.SPITXBUF=0xFA00; // Transmit start Char Order (8 bits left justified on 16 bits) while ( ! SpiaRegs.SPISTS.bit.INT_FLAG ) {} SpiaRegs.SPIRXBUF=SpiaRegs.SPIRXBUF; // clear le SPISTS,BIT6 : donnée_envoyé SpiaRegs.SPITXBUF=low<<8; // 8 bits left justified on 16 bits while ( ! SpiaRegs.SPISTS.bit.INT_FLAG ) {} SpiaRegs.SPIRXBUF=SpiaRegs.SPIRXBUF; // clear le SPISTS,BIT6 : donnée_envoyé SpiaRegs.SPITXBUF=hi<<8; // 8 bits left justified on 16 bits while ( ! SpiaRegs.SPISTS.bit.INT_FLAG ) {} SpiaRegs.SPIRXBUF=SpiaRegs.SPIRXBUF; // clear le SPISTS,BIT6 : donnée_envoyé LCD_CS=1; // Desacive le LCD via le /CS } //---------------------------------------------------- // Envoi 3 bytes pour Afficher : ordre requiert hi et low //---------------------------------------------------- inline void DispLCDOrder(int hi, int low) { // debug : voir si on peut utiliser le fifo pour alleger le cpu LCD_CS=0; // Active le LCD via le /CS // SpiaRegs.SPIRXBUF=SpiaRegs.SPIRXBUF; // clear le SPISTS,BIT6 SpiaRegs.SPITXBUF=0xF800; // Transmit start Ordre (8 bits left justified on 16 bits) while ( ! SpiaRegs.SPISTS.bit.INT_FLAG ) {} SpiaRegs.SPIRXBUF=SpiaRegs.SPIRXBUF; // clear le SPISTS,BIT6 : donnée_envoyé SpiaRegs.SPITXBUF=low<<8; // 8 bits left justified on 16 bits while ( ! SpiaRegs.SPISTS.bit.INT_FLAG ) {} SpiaRegs.SPIRXBUF=SpiaRegs.SPIRXBUF; // clear le SPISTS,BIT6 : donnée_envoyé SpiaRegs.SPITXBUF=hi<<8; // 8 bits left justified on 16 bits while ( ! SpiaRegs.SPISTS.bit.INT_FLAG ) {} SpiaRegs.SPIRXBUF=SpiaRegs.SPIRXBUF; // clear le SPISTS,BIT6 : donnée_envoyé LCD_CS=1; // Desacive le LCD via le /CS } |
According to the previous graph, the bits order is D0 to D7, but the SPI send the Hi bit first (MSB) (ie. from D7 to D0). So you have to implement a routine or macro, let's call it trChar (see below).
Char Table
trChar function description
This inline function inverts the byte to be sent. Form D0 through D7, it becomes D7 through D0.Then it creates two bytes : LCDlo and LCDhi, that have only half of them that is non zero, according to the communication diagram.
//---------------------------------------------------- // Routine trChar : transforme le char LCDChar en LCDChar_m (pour le LCD) //---------------------------------------------------- inline void trChar() { Uint16 tmp; LCDChar_m=0x00; for (tmp=8; tmp>0; tmp--) { LCDChar_m=LCDChar_m<<1 | (LCDChar & 1); LCDChar=LCDChar>>1; } LCDlo=LCDChar_m & 0xF0; LCDhi=LCDChar_m<<4 & 0xF0; } |
ConvHexa function description
This inline function converts from an Hexa word to 4 ASCII chars and put them in the buffer LCDtable.//---------------------------------------------------- // Convertit un "Word" hexa en "4 chars Hexadécimaux" // et les sort sur la table en memoire //---------------------------------------------------- inline void ConvHexa(int Var, int LCDtablePos) { Uint16 tmp; tmp=Var & 0x000F; if (tmp<=9) tmp+=0x30; else tmp+=0x37; LCDtable[LCDtablePos+3]=tmp; tmp=Var>>4 & 0x000F; if (tmp<=9) tmp+=0x30; else tmp+=0x37; LCDtable[LCDtablePos+2]=tmp; tmp=Var>>8 & 0x000F; if (tmp<=9) tmp+=0x30; else tmp+=0x37; LCDtable[LCDtablePos+1]=tmp; tmp=Var>>12 & 0x000F; if (tmp<=9) tmp+=0x30; else tmp+=0x37; LCDtable[LCDtablePos]=tmp; } |
LCD instruction Table
This table is extracted from the full SAMSUNG KS0074 pdf driver file or from the SELTRONIC LCD pdf file : Instructions.pdfRefresh the screen
An intersting use of this LCD screen is to display internal variables of the F2812 program that is real time running.
According to an interrupt, let say every 100 us, we could write one character at a time.
So you can implement a table (2x16 characters) in memory where you write variables in Hex or Decimal (look at the page : Hex to Decimal conversion).
Every sampling period, you will check if you have to refresh the LCD screen and write 1 characters from the table to the LCD driver via the SPI interface.
Of course, for each character, you will invert its byte (D0 to D7), split it in 2 bytes of 4 bits significants data bits and zeroes the others bits, then sending the 3 bytes (header, LCDlo and LCDhi) on the SPI.
This is done with :
//---------------------------------------------------- // Routine d envoi de donnees sur SPI (pour LCD) // met à jour la LCDtable sur l écran //---------------------------------------------------- inline void AfficheLCDTable() { LCDChar=LCDtable[LCDcol]; trChar(); DispLCDChar( LCDhi, LCDlo); // sortir le Char actuel et inutile d attendre car routine ttes les 100 us if (++LCDcol>=32) { LCDcol=0; LCDupdate=2; // demande de remise à la 1er ligne du curseur } } |
It works fine... and leave you enough time, within the 100 us sampling period, for sending on the SPI 2 bytes for TLV 5614 DAC refresh and for performing a V/f motor control... DSPs run incredibly fast :-)
Configuration of GPIO (Input/Output ports) and Clocks prescalers
These lines configure the Hi Speed Clock and the load speed one based on a 150 MHz System clock.// For this example, set HSPCLK to SYSCLKOUT / 6 (25Mhz assuming 150Mhz SYSCLKOUT) EALLOW; // SysCtrlRegs.HISPCP.all = 0x3; // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 150/(2*3) = 25MHz SysCtrlRegs.HISPCP.all = 0x1; // HSPCLK = SYSCLKOUT/2 = 75 MHz (System Reset) SysCtrlRegs.LOSPCP.all = 0x2; // LOPCLK = SYSCLKOUT/4 = 54 MHz (System Reset) // Enable PWM pins GpioMuxRegs.GPAMUX.all = 0x00FF; // EVA PWM 1-6 pins GpioMuxRegs.GPBMUX.all = 0x00FF; // EVB PWM 7-12 pins GpioMuxRegs.GPFMUX.all=0x000F; // Select GPIOs to be SPI pins GpioMuxRegs.GPFMUX.bit.XF_GPIOF14 = 1; // XF active GpioMuxRegs.GPGMUX.all = 0x0000; // LCD_CS GPIOG4 and Gyro_CS GPIOG5 GpioMuxRegs.GPGDIR.all = 0x0030; // CS are outpout EDIS; |
Configuration of ADC and its ISR (Interrupt Service Routine)
These lines configure the ISR routine name to adc_isr, ADC channels, ADC SOC (Start Of Conversion) events which will be the event manager A and the ADC Clock prescaler.// Interrupts that are used in this example are re-mapped to // ISR functions found within this file. EALLOW; // This is needed to write to EALLOW protected register PieVectTable.ADCINT = &adc_isr; EDIS; // This is needed to disable write to EALLOW protected registers // Step 4. Initialize all the Device Peripherals: // This function is found in DSP281x_InitPeripherals.c // InitPeripherals(); // Not required for this example InitAdc(); // For this example, init the ADC init_ev(); init(); // init my variables // Configure ADC AdcRegs.ADCMAXCONV.all = 0x0005; // Setup 6 convs on SEQ1 AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x0; // Setup ADCINA0 as 1st SEQ1 conv. AdcRegs.ADCCHSELSEQ1.bit.CONV01 = 0x1; // Setup ADCINA1 as 2nd SEQ1 conv. AdcRegs.ADCCHSELSEQ1.bit.CONV02 = 0x2; // Setup ADCINA2 as 3rd SEQ1 conv. AdcRegs.ADCCHSELSEQ1.bit.CONV03 = 0x3; // Setup ADCINA3 as 4th SEQ1 conv. AdcRegs.ADCCHSELSEQ2.bit.CONV04 = 0x4; // Setup ADCINA4 as 5th SEQ1 conv. AdcRegs.ADCCHSELSEQ2.bit.CONV05 = 0x5; // Setup ADCINA5 as 6th SEQ1 conv. AdcRegs.ADCTRL2.bit.EVA_SOC_SEQ1 = 1; // Enable EVASOC to start SEQ1 AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 1; // Enable SEQ1 interrupt (every EOS) AdcRegs.ADCTRL3.bit.ADCCLKPS = 0x6; // ADC peripheral clk divider = /6 AdcRegs.ADCTRL1.bit.CPS = 0; // encore un ADC peripheral clk prescaler =/1 |
Configuration of Event Manager A and B (timers, PWM) and main() function
These lines configure timers 1 and 3 of Event manager (EV) A and B respectively.//-------------------------------------------------------------------------- void init_ev() { // Configure EVA // Assumes EVA Clock is already enabled in InitSysCtrl(); EvaRegs.T1PR = FullDuty; // Setup period register MLI à 16 kHz=62.5 us EvaRegs.T1CNT = 0x0000; // Timer1 counter EvaRegs.GPTCONA.bit.T1TOADC = 0x2; // Enable EVASOC in EVA on PRD match EvaRegs.T1CON.all = 0x8800; // prepare T1, disable (up & down count mode) // EVA Configure PWM1-PWM6 // Enable compare for PWM1-PWM6 EvaRegs.CMPR1 = HalfDuty; EvaRegs.CMPR2 = HalfDuty-300; EvaRegs.CMPR3 = 20; // Compare action control. Action that takes place on a cmpare event // output pin 1 CMPR1 - active low // output pin 2 CMPR1 - active high // output pin 3 CMPR2 - active low // output pin 4 CMPR2 - active high // output pin 5 CMPR3 - active low // output pin 6 CMPR3 - active high EvaRegs.ACTRA.all = 0x0999; EvaRegs.DBTCONA.all = 0x0000; // Disable deadband EvaRegs.COMCONA.all = 0xA600; // Configure EVB // Initialize EVB Timer3 // Timer3 controls T3PWM and PWM7-12 EvbRegs.T3PR = FullDuty; // Timer3 period EvbRegs.T3CNT = 0x0000; // Timer3 counter EvbRegs.T3CON.all = 0x8800; // prepare T3, disable (up & down count mode) // // Enable compare for PWM7-PWM12 EvbRegs.CMPR4 = HalfDuty; EvbRegs.CMPR5 = HalfDuty-300; EvbRegs.CMPR6 = 20; // Compare action control. Action that takes place // on a cmpare event // output pin 1 CMPR4 - active low // output pin 2 CMPR4 - active high // output pin 3 CMPR5 - active low // output pin 4 CMPR5 - active high // output pin 5 CMPR6 - active low // output pin 6 CMPR6 - active high EvbRegs.ACTRB.all = 0x0999; EvbRegs.DBTCONB.all = 0x0000; // Disable deadband EvbRegs.COMCONB.all = 0xA600; } //-------------------------------------------------------------------------- |
When the timers and PWM are set, we enable the interrupts (ADCINT) and global interrupt (INTM).
We also start timers 1 and 3 of Event manager (EV) A and B respectively.
We then go in the infinite main loop.
// Enable ADCINT in PIE PieCtrlRegs.PIEIER1.bit.INTx6 = 1; IER |= M_INT1; // Enable CPU Interrupt 1 EINT; // Enable Global interrupt INTM ERTM; // Enable Global realtime interrupt DBGM // start Timer1 and 3 EvaRegs.T1CON.bit.TENABLE = 1; // Enable timer 1 counting (up & down count mode) EvbRegs.T3CON.bit.TENABLE = 1; // Enable timer 3 counting (up & down count mode) // Wait for ADC interrupt while(1) { } |
l'ISR adc_int
This is the interrupt service routine that is called every 62.5 us.It reads the ADC register buffers to get the references and current measures. It the sets the PWM duty cylces CMPRx.
This of course is only an exemple, because the duty cycle has to be computed through a Park transformation...
Then an LCD memory buffer update is done through the call of different functions.
//-------------------------------------------------------------------------- interrupt void adc_isr(void) { asm(" setc XF "); // Set XF for monitoring LED on Ref1= AdcRegs.ADCRESULT0 >>4; Ref2= AdcRegs.ADCRESULT1 >>4; Iar = AdcRegs.ADCRESULT2 >>4; Ibr = AdcRegs.ADCRESULT3 >>4; Ial = AdcRegs.ADCRESULT4 >>4; Ibl = AdcRegs.ADCRESULT5 >>4; // Reinitialize for next ADC sequence AdcRegs.ADCTRL2.bit.RST_SEQ1 = 1; // Reset SEQ1 AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1; // Clear INT SEQ1 bit PieCtrlRegs.PIEACK.all = PIEACK_GROUP1; // Acknowledge interrupt to PIE // change rapport cyclique // Moteur Right EvaRegs.CMPR1 = Ref2; EvaRegs.CMPR2 = Ref2; EvaRegs.CMPR3 = Ref2; // Moteur Left EvbRegs.CMPR4 = FullDuty-MyAlpha; EvbRegs.CMPR5 = FullDuty-MyAlpha; EvbRegs.CMPR6 = FullDuty-MyAlpha; // mise à jour d une phrase // sprintf(Str_Ialim,"-none-"); switch (LCDupdate) { case 1 : AfficheLCDTable(); break; case 2 : LCDupdate=0; DispLCDOrder( 0x00, 0x40); //Retour curseur à l origine break; default: // si zero alors demande la MAJ des I1 et I2 // execute toutes les (1000+32+1)*100 us if (--SeqComm>=0) break; SeqComm=SeqCommMax; LCDupdate=1; // Cursor home ConvHexa(Ref1, offsRef1); // Ref1 en Hexa ConvHexa(Ref2, offsRef2); // Ref1 en Hexa // LCDtable[offsH+2]=HallA+0x30; // LCDtable[offsH+1]=HallB+0x30; // LCDtable[offsH ]=HallC+0x30; // LCDtable[offsS]=Secteur+0x30; LCDtable[offsI ]=Str_Ialim[0]; LCDtable[offsI+1]=Str_Ialim[1]; LCDtable[offsI+2]=Str_Ialim[2]; LCDtable[offsI+3]=Str_Ialim[3]; LCDtable[offsI+4]=Str_Ialim[4]; LCDtable[offsI+5]=Str_Ialim[5]; } // fin eteint la diode et sort asm(" clrc XF "); // Clear XF for monitoring LED off } |