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////////////////////////////////////////////////////////////////////////////////

//

// Filename:    oledtest.c

//

// Project:     OpenArty, an entirely open SoC based upon the Arty platform

//

// Purpose:     To see whether or not we can display an image onto the OLEDrgb

//              PMod.  This program runs on the ZipCPU internal to the FPGA,

//      and commands the OLEDrgb to power on, reset, initialize, and then to

//      display an alternating pair of images onto the display.

//

//

// Creator:     Dan Gisselquist, Ph.D.

//              Gisselquist Technology, LLC

//

////////////////////////////////////////////////////////////////////////////////

//

// Copyright (C) 2015-2016, Gisselquist Technology, LLC

//

// This program is free software (firmware): you can redistribute it and/or

// modify it under the terms of  the GNU General Public License as published

// by the Free Software Foundation, either version 3 of the License, or (at

// your option) any later version.

//

// This program is distributed in the hope that it will be useful, but WITHOUT

// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with this program.  (It's in the $(ROOT)/doc directory, run make with no

// target there if the PDF file isn't present.)  If not, see

// <http://www.gnu.org/licenses/> for a copy.

//

// License:     GPL, v3, as defined and found on www.gnu.org,

//              http://www.gnu.org/licenses/gpl.html

//

//

////////////////////////////////////////////////////////////////////////////////

//

//

#include "zipcpu.h"

#include "zipsys.h"

#include "artyboard.h"

void    idle_task(void) {

        while(1)

                zip_idle();

}

extern int      splash[], mug[];

#define OLED_DISPLAYON          0x0af

#define MICROSECOND             (CLOCKFREQ_HZ/1000000)

#define OLED_DISPLAY_OFF

/*

 * timer_delay()

 *

 * Using the timer peripheral, delay by a given number of counts.  We'll sleep

 * during this delayed time, and wait on an interrupt to wake us.  As a result,

 * this will only work from supervisor mode.

 */

void    timer_delay(int counts) {

        // Clear the PIC.  We want to exit from here on timer counts alone

        zip->z_pic = CLEARPIC;

        if (counts > 10) {

                // Set our timer to count down the given number of counts

                zip->z_tma = counts;

                zip->z_pic = EINT(SYSINT_TMA);

                zip_rtu();

                zip->z_pic = CLEARPIC;

        } // else anything less has likely already passed

}

void    wait_on_interrupt(int mask) {

        // Clear our interrupt only, but disable all others

        zip->z_pic = DALLPIC|mask;

        zip->z_pic = EINT(mask);

        zip_rtu();

        zip->z_pic = DINT(mask)|mask;

}

void oled_clear(void);

/*

 * The following outlines a series of commands to send to the OLEDrgb as part

 * of an initialization sequence.  The sequence itself was taken from the

 * MPIDE demo.  Single byte numbers in the sequence are just that: commands

 * to send 8-bit values across the port.  17-bit values with the 16th bit

 * set send two bytes (bits 15-0) to the port.  The OLEDrgb treats these as

 * commands (first byte) with an argument (the second byte).

 */

const int       init_sequence[] = {

        //  Unlock commands

        0x01fd12,

        //  Display off

        0x0ae,

        //  Set remap and data format

        0x01a072,

        //  Set the start line

        0x01a100,

        //  Set the display offset

        0x01a200,

        //  Normal display mode

        0x0000a4,

        //  Set multiplex ratio

        0x01a83f,

        //  Set master configuration:

        //      Use External VCC

        0x01ad8e,

        //  Disable power save mode

        0x01b00b,

        //  Set phase length

        0x01b131,

        //  Set clock divide

        0x01b3f0,

        //  Set Second Pre-change Speed For ColorA

        0x018a64,

        //  5l) Set Set Second Pre-charge Speed of Color B

        0x018b78,

        //  5m) Set Second Pre-charge Speed of Color C

        0x018c64,

        //  5n) Set Pre-Charge Voltage

        0x01bb3a,

        //  50) Set VCOMH Deselect Level

        0x01be3e,

        //  5p) Set Master Current

        0x018706,

        //  5q) Set Contrast for Color A

        0x018191,

        //  5r) Set Contrast for Color B

        0x018250,

        //  5s) Set Contrast for Color C

        0x01837D,

        //  disable scrolling

        0x02e

};

/*

 * oled_init()

 *

 * This initializes and starts up the OLED.  While it sounds important, really

 * the majority of the work necessary to do this is really captured in the

 * init_sequence[] above.  This just primarily works to send that sequence to

 * the PMod.

 *

 * We should be able to do all of this with the DMA: wait for an OLEDrgb not

 * busy interrupt, send one value, repeat until done.  For now ... we'll just

 * leave that as an advanced exercise.

 *

 */

void    oled_init(void) {

        int     i;

        for(i=0; i<sizeof(init_sequence); i++) {

                while(OLED_BUSY(sys->io_oled))

                        ;

                sys->io_oled.o_ctrl = init_sequence[i];

        }

        oled_clear();

        // Wait 5ms

        timer_delay(CLOCKFREQ_HZ/200);

        // Turn on VCC and wait 100ms

        sys->io_oled.o_data = OLED_VCCEN;

        // Wait 100 ms

        timer_delay(CLOCKFREQ_HZ/10);

        // Send Display On command

        sys->io_oled.o_ctrl = OLED_DISPLAYON;

}

/*

 * oled_clear()

 *

 * This should be fairly self-explanatory: it clears (sets to black) all of the

 * graphics memory on the OLED.

 *

 * What may not be self-explanatory is that to send any more than three bytes

 * using our interface you need to send the first three bytes in o_ctrl,

 * and set the next bytes (up to four) in o_a.  (Another four can be placed in

 * o_b.)  When the word is written to o_ctrl, the command goes over the wire

 * and o_a and o_b are reset.  Hence we set o_a first, then o_ctrl.  Further,

 * the '4' in the top nibble of o_ctrl indicates that we are sending 5-bytes

 * (4+5), so the OLEDrgb should see: 0x25,0x00,0x00,0x5f,0x3f.

 */

void    oled_clear(void) {

        while(OLED_BUSY(sys->io_oled))

                ;

        sys->io_oled.o_a = 0x5f3f0000;

        sys->io_oled.o_ctrl = 0x40250000;

        while(OLED_BUSY(sys->io_oled))

                ;

}

/*

 * oled_fill

 *

 * Similar to oled_clear, this fills a rectangle with a given pixel value.

 */

void    oled_fill(int c, int r, int w, int h, int pix) {

        int     ctrl; // We'll send this value out the control/command port

        if (c > 95) c = 95;

        if (c <  0) c =  0;

        if (r > 63) r = 63;

        if (r <  0) r =  0;

        if (w <  0) w = 0;

        if (h <  0) h = 0;

        if (c+w > 95) w = 95-c;

        if (r+h > 63) h = 63-r;

        // Enable the fill rectangle function, rather than just the outline

        while(OLED_BUSY(sys->io_oled))

                ;

        sys->io_oled.o_ctrl = 0x12601;

        //

        // Now, let's build the actual copy command

        //

        // This is an 11 byte command, consisting of the 0x22, followed by

        // the top left column and row of our rectangle, and then the bottom

        // right column and row.  That's the first five bytes.  The next six

        // bytes are the color of the border and the color of the fill.

        // Here, we set both colors to be identical.

        // 

        ctrl = 0xa0220000 | ((c&0x07f)<<8) | (r&0x03f);

        sys->io_oled.o_a = (((c+w)&0x07f)<<24) | (((r+h)&0x03f)<<16);

        sys->io_oled.o_a|= ((pix >> 11) & 0x01f)<< 9;

        sys->io_oled.o_a|= ((pix >>  5) & 0x03f)    ;

        sys->io_oled.o_b = ((pix      ) & 0x01f)<<25;

        sys->io_oled.o_b|= ((pix >> 11) & 0x01f)<<17;

        sys->io_oled.o_b|= ((pix >>  5) & 0x03f)<< 8;

        sys->io_oled.o_b|= ((pix      ) & 0x01f)<< 1;

        // Make certain we had finished with the port

        while(OLED_BUSY(sys->io_oled))

                ;

        // and send our new command.  Note that o_a and o_b were already set

        // ahead of time, and are only now being sent together with this

        // command.

        sys->io_oled.o_ctrl = ctrl;

        // To be nice to whatever routine follows, we'll wait 'til the port

        // is clear again.

        while(OLED_BUSY(sys->io_oled))

                ;

}

/*

 * oled_show_image(int *img)

 *

 * This is a really simply function, for a really simple purpose: it copies

 * a full size image to the device.  You'll notice two versions of the routine

 * below.  They are roughly identical in what they do.  The first version

 * sets up the DMA to transfer the data, one word at a time, from RAM to

 * the OLED.  One byte is transferred every at every OLED interrupt.  The other

 * version works roughly the same way, but first waits for the OLED port to be

 * clear before sending the image.  The biggest difference between the two

 * approaches is that, when using the DMA, the routine finishes before the

 * DMA transfer is complete, whereas the second version of the routine

 * returns as soon as the image transfer is complete.

 */

void    oled_show_image(int *img) {

#define USE_DMA

#ifdef  USE_DMA

                zip->z_dma.d_len= 6144;

                zip->z_dma.d_rd = img;

                zip->z_dma.d_wr = (int *)&sys->io_oled.o_data;

                zip->z_dma.d_ctrl = DMAONEATATIME|DMA_CONSTDST|DMA_ONOLED;

#else

                for(int i=0; i<6144; i++) {

                        while(OLED_BUSY(sys->io_oled))

                                ;

                        sys->io_oled.o_data = img[i];

                }

#endif

}

/*

 * entry()

 *

 * In all (current) ZipCPU programs, the programs start with an entry()

 * function that takes no arguments.  The actual bootup entry can be found

 * in the bootstrap.c file, but that calls us here.

 *

 */

void    main(int argc, char **argv) {

        // Since we'll be returning to userspace via zip_rtu() in order to

        // wait for an interrupt, let's at least place a valid program into

        // userspace to run: the idle_task.

        unsigned        user_regs[16];

        for(int i=0; i<15; i++)

                user_regs[i] = 0;

        user_regs[15] = (unsigned int)idle_task;

        zip_restore_context(user_regs);

        // Clear the PIC.  We'll come back and use it later.  We clear it here

        // partly in order to avoid a race condition later.

        zip->z_pic = CLEARPIC;

        // Wait till we've had power for at least a quarter second

        if (0) {

                // While this appears to do the task quite nicely, it leaves

                // the master_ce line high within the CPU, and so it generates

                // a whole lot of debug information in our Verilator simulation,

                // busmaster_tb.

                int pwrcount = sys->io_pwrcount;

                do {

                        pwrcount = sys->io_pwrcount;

                } while((pwrcount>0)&&(pwrcount < CLOCKFREQ_HZ/4));

        } else {

                // By using the timer and sleeping instead, the simulator can

                // be made to run a *lot* faster, with a *lot* less debugging

                // ... junk.

                int pwrcount = sys->io_pwrcount;

                if ((pwrcount > 0)&&(pwrcount < CLOCKFREQ_HZ/4)) {

                        pwrcount = CLOCKFREQ_HZ/4 - pwrcount;

                        timer_delay(pwrcount);

                }

        }

        // If the OLED is already powered, such as might be the case if

        // we rebooted but the board was still hot, shut it down

        if (sys->io_oled.o_data & 0x07) {

                sys->io_oled.o_data = OLED_VCC_DISABLE;

                // Wait 100 ms

                timer_delay(CLOCKFREQ_HZ/10);

                // Shutdown the entire devices power

                sys->io_oled.o_data = OLED_POWER_DOWN;

                // Wait 100 ms

                timer_delay(CLOCKFREQ_HZ/10);

                // Now let's try to restart it

        }

        // 1. Power up the OLED by applying power to VCC

        //      This means we need to apply power to both the VCCEN line as well

        //      as the PMODEN line.  We'll also set the reset line low, so the

        //      device starts in a reset condition.

        sys->io_oled.o_data = OLED_PMODEN|OLED_RESET_CLR;

        timer_delay(4*MICROSECOND);

        sys->io_oled.o_data = OLED_RESET;

        timer_delay(4*MICROSECOND);

        // 2. Send the Display OFF command

        //      This isn't necessary, since we already pulled RESET low.

        //

        // sys->io_oled.o_ctrl = OLED_DISPLAY_OFF;

        //

        // However, we must hold the reset line low for at least 3us, as per

        // the spec.  We may also need to wait another 2us after that.  Let's

        // hold reset low for 4us here.

        timer_delay(4*MICROSECOND);

        // Clear the reset condition.

        sys->io_oled.o_data = OLED_RESET_CLR;

        // Wait another 4us.

        timer_delay(4*MICROSECOND);

        // 3. Initialize the display to the default settings

        //      This just took place during the reset cycle we just completed.

        //

        oled_init();

        // 4. Clear screen

        // 5. Apply voltage

        // 6. Turn on display

        // 7. Wait 100ms

        //      We already stuffed this command sequence into the oled_init,

        //      so we're good here.

        while(1) {

                sys->io_ledctrl = 0x0f0;

                sys->io_oled.o_ctrl = OLED_DISPLAYON;

                oled_clear();

                // Let's start our writes at the top left of the GDDRAM

                // (screen memory)

                while(OLED_BUSY(sys->io_oled))

                        ;

                sys->io_oled.o_ctrl = 0x2015005f; // Sets column min/max address

                while(OLED_BUSY(sys->io_oled))

                        ;

                sys->io_oled.o_ctrl = 0x2075003f; // Sets row min/max address

                while(OLED_BUSY(sys->io_oled))

                        ;

                // Now ... finally ... we can send our image.

                oled_show_image(splash);

                wait_on_interrupt(SYSINT_DMAC);

                // Wait 25 seconds.  The LEDs are for a fun effect.

                sys->io_ledctrl = 0x0f1;

                timer_delay(CLOCKFREQ_HZ*5);

                sys->io_ledctrl = 0x0f3;

                timer_delay(CLOCKFREQ_HZ*5);

                sys->io_ledctrl = 0x0f7;

                timer_delay(CLOCKFREQ_HZ*5);

                sys->io_ledctrl = 0x0ff;

                timer_delay(CLOCKFREQ_HZ*5);

                sys->io_ledctrl = 0x0fe;

                timer_delay(CLOCKFREQ_HZ*5);

                // Display a second image.

                sys->io_ledctrl = 0x0fc;

                oled_show_image(mug);

                wait_on_interrupt(SYSINT_DMAC);

                // Leave this one in effect for 5 seconds only.

                sys->io_ledctrl = 0x0f8;

                timer_delay(CLOCKFREQ_HZ*5);

        }

        // We'll never get here, so this line is really just for form.

        zip_halt();

}