RA8876LiteTeensy For Teensy T36 and T40
- Thread starter wwatson
- Start date
@beumerjm
Actually you can also just do tft.println or tft.print or tft.prinnt at the cursor postion
haha, thanks - I figured there was a simpler way. Is the putString function much slower? I like that I can specify the position in the function, just keep to keep the lines of code down as I'm printing things all over the screen.
wwatson
Well-known member
Hi beumerjm,
I put in a weekend working on this. The RA8876 is going to be difficult to to implement full rotation with text. It seems to be geared more towards graphic rotation than text screen rotation. It will rotate text characters 90 degrees but that seems to be all. (Unless I am missing something). I am thinking that user defined characters defined in the three remaining angles my work but that's a lot of work. I have not had time to play with that any more.There are registers in RA8876 the change the origin and direction of the screen writes. Clear as mud HUH
Same with me...Hi beumerjm,
I put in a weekend working on this. The RA8876 is going to be difficult to to implement full rotation with text. It seems to be geared more towards graphic rotation than text screen rotation. It will rotate text characters 90 degrees but that seems to be all. (Unless I am missing something). I am thinking that user defined characters defined in the three remaining angles my work but that's a lot of work. I have not had time to play with that any more.There are registers in RA8876 the change the origin and direction of the screen writes. Clear as mud HUH
haha, no worries, thanks! I did discover that what I was implementing was working for flipping graphics, but only image imports. I thought it would work for drawing geometry, but it only affects the rotation for reading in bitmap images and displaying them. I guess I will look into how to rotate text and either just figure out the coordinates for all of the other shapes I need or import them as an image, TBD. Thanks for all of your work on this!
MorganS
Well-known member
Rotation is one of the issues I looked at. It seems the way I want to mount these screens is always upside-down from their default rotation.
Unfortunately it seems like the RA8876 wasn't designed with this in mind. There may be something buried deep in the text handling registers but a second look hasn't shown a method for rotating text properly.
The next step I'm working on is LittlevGL. That doesn't use the RA8876 text functions, or any function except bulk-loading rectangles of pixels onto the screen. It will do rotation itself.
Unfortunately it seems like the RA8876 wasn't designed with this in mind. There may be something buried deep in the text handling registers but a second look hasn't shown a method for rotating text properly.
The next step I'm working on is LittlevGL. That doesn't use the RA8876 text functions, or any function except bulk-loading rectangles of pixels onto the screen. It will do rotation itself.
KurtE
Senior Member+
Wonder how close the rotation stuff is to the RA8875 display? I know there is screwy stuff in it. Example things like writeRect has to manually switch the direction of the bits... Maybe they are completely different, but that would be one place I would suggest taking a look.
MorganS
Well-known member
Rectangles and other graphic objects are easy. The RA8875 library shows how to do that.
You do need to be careful with the variables for physical widthXheight and currently-rotated widthXheight but it just takes work to slog through the code and ensure the correct one is used in the correct place.
The problem with the RA8876 is it can't rotate the text writing direction. It can mirror a character when writing it to the screen but it can't rotate 90 degrees. The RA8875 could use a combination of mirror and rotate to put the text in 4 orientations but the RA8876 seems to be missing the rotation. It may be that the datasheet is simply incomplete and there's a hidden register in there but it seems unlikely that the datasheet author missed it. Maybe load a custom font that's rotated and then update the text cursor after every character?
You do need to be careful with the variables for physical widthXheight and currently-rotated widthXheight but it just takes work to slog through the code and ensure the correct one is used in the correct place.
The problem with the RA8876 is it can't rotate the text writing direction. It can mirror a character when writing it to the screen but it can't rotate 90 degrees. The RA8875 could use a combination of mirror and rotate to put the text in 4 orientations but the RA8876 seems to be missing the rotation. It may be that the datasheet is simply incomplete and there's a hidden register in there but it seems unlikely that the datasheet author missed it. Maybe load a custom font that's rotated and then update the text cursor after every character?
MorganS
Well-known member
Well, it wasn't as simple as I thought to plug in the LittlevGL library. And it doesn't do screen rotations. (Although it might be possible in the driver code you have to write.)
This is a simple demo that has only one slider widget. It uses the capacative touchscreen on the 7" RA8876 screen. The full screen redraw takes about 200ms with SPI set to 75MHz. Fast enough that you don't really notice it. (Next test will try full-screen sized scrolling.)
This is a simple demo that has only one slider widget. It uses the capacative touchscreen on the 7" RA8876 screen. The full screen redraw takes about 200ms with SPI set to 75MHz. Fast enough that you don't really notice it. (Next test will try full-screen sized scrolling.)
Code:
/* Demonstrate LvGL library on RA8876 screen with Teensy4 (but should work on other Arduino-based platforms) */
#include <lvgl.h> //in lv_arduino library: https://github.com/lvgl/lv_arduino
#include <RA8876_t3.h>
#include <MsTimer2.h> //One of the standard timer libraries included with Teensy - could use TimerOne or TimerThree if you prefer
#ifdef SPI_HAS_TRANSFER_ASYNC
#include "EventResponder.h" //Standard library in Teensy required for SPI direct memory access
#endif
#include <FT5206.h> //Works on any FocalTech capacative touch controller (all screen sizes under 8")
const int screenWidth = 1024;
const int screenHeight = 600;
#define BUFFER_SIZE (screenWidth * 50) //recommended is *10 but this sketch has nothing else useful to do with the memory available on Teensy 4, so go large!
#define RA8876_CS 10
#define RA8876_RESET 23
#define BACKLITE 14 //My copy of the display is set for external backlight control
RA8876_t3 tft = RA8876_t3(RA8876_CS, RA8876_RESET); //Using standard SPI pins
#define CTP_INT 0 // Use an interrupt capable pin such as pin 2 (any pin on a Teensy)
FT5206 cts = FT5206(CTP_INT);
/*A static or global variable to store the buffers*/
static lv_disp_buf_t disp_buf;
/*Static or global buffers. The second buffer is used while DMA is uploading the first buffer*/
static lv_color_t buf_1[BUFFER_SIZE];
static lv_color_t buf_2[BUFFER_SIZE];
lv_disp_drv_t disp_drv; /*A variable to hold the drivers. Can be local variable*/
lv_disp_t * disp;
#define LED_PIN 1 //optionally connect an LED to this pin to see it dimming
#define LVGL_TICK_PERIOD 1
lv_obj_t * slider_label;
#ifdef SPI_HAS_TRANSFER_ASYNC
EventResponder spiDMAEvent;
//**************************************************************//
// If using DMA, must close transaction and de-assert _CS
// after the data has been sent.
//**************************************************************//
void spiEventResponder(EventResponderRef event_responder) {
lv_disp_drv_t *disp = (lv_disp_drv_t*)event_responder.getContext();
tft.activeDMA = false;
tft.endSend(true);
lv_disp_flush_ready(disp);
}
#endif
void my_disp_flush(lv_disp_drv_t *disp, const lv_area_t *area, lv_color_t *color_p)
{
uint16_t width = (area->x2 - area->x1 + 1);
uint16_t height = (area->y2 - area->y1 + 1);
/*
Serial.print("Flushing row ");
Serial.print(area->y1);
Serial.print(" millis ");
Serial.print(millis());
Serial.println();
*/
tft.bteMpuWriteWithROP(tft.currentPage, tft.width(), area->x1, area->y1, //Source 1 is ignored for ROP12
tft.currentPage, tft.width(), area->x1, area->y1, width, height, //destination address, pagewidth, x/y, width/height
RA8876_BTE_ROP_CODE_12); //code 12 means overwrite
tft.startSend();
SPI.transfer(RA8876_SPI_DATAWRITE);
#ifdef SPI_HAS_TRANSFER_ASYNC
tft.activeDMA = true;
spiDMAEvent.setContext(disp); // Set the contxt to us
SPI.transfer(color_p, NULL, width * height * 2, spiDMAEvent);
#else
SPI.transfer(color_p, NULL, width * height * 2);
tft.endSend(true);
lv_disp_flush_ready(disp);
#endif
}
bool my_touchpad_read(lv_indev_drv_t * indev_driver, lv_indev_data_t * data)
{
//The cts_touched() is set by an interrupt whenever something changes on the touch panel
//So many times that you call this, touched is false even when a finger is held against the panel,
//it just hasn't moved.
//But, when the last finger is removed, we get one final "touched" event telling us that the
//number of touches is zero. Very useful.
uint8_t registers[FT5206_REGISTERS];
uint16_t new_coordinates[5][2];
uint8_t current_touches = 0;
static int16_t touchX, touchY;
if (cts.touched())
{
cts.getTSregisters(registers);
current_touches = cts.getTScoordinates(new_coordinates, registers);
if (current_touches < 1) {
//No touches - this is a "release" - all fingers lifted off the panel
data->state = LV_INDEV_STATE_REL;
} else {
//Current touches can be more than 1 but we can't use multiple fingers.
//(LvGL doesn't have pinch-zoom or 3-finger swipe actions.)
//Just get the first touch out of the first entry in the cooordinates array.
data->state = LV_INDEV_STATE_PR;
//Touch panel is upside-down to the screen coordinates, so we must subtract
touchX = screenWidth - new_coordinates[0][0] - 1;
touchY = screenHeight - new_coordinates[0][1] - 1;
//Set the coordinates (if released use the last pressed coordinates)
data->point.x = touchX;
data->point.y = touchY;
/*
Serial.print("Touch x");
Serial.print(touchX);
Serial.print(" y");
Serial.println(touchY);
*/
}
}
return false; //Return `false` because we are not buffering and no more data to read
}
/* Interrupt driven periodic handler */
static void myTick(void)
{
lv_tick_inc(LVGL_TICK_PERIOD);
}
void slider_event_cb(lv_obj_t * slider, lv_event_t event)
{
printEvent("Slider", event);
if (event == LV_EVENT_VALUE_CHANGED) {
static char buf[4]; /* max 3 bytes for number plus 1 null terminating byte */
snprintf(buf, 4, "%u", lv_slider_get_value(slider));
lv_label_set_text(slider_label, buf); /*Refresh the text*/
int16_t value = lv_slider_get_value(slider);
value = map(value, 0, 100, 0, 255);
//analogWriteFrequency(2000); // Set PMW period to 2000 Hz instead of 1000
analogWrite(LED_PIN, value);//8-bit by default
}
}
void printEvent(String Event, lv_event_t event)
{
Serial.print(Event);
Serial.printf(" ");
switch (event) {
case LV_EVENT_PRESSED:
Serial.printf("Pressed\n");
break;
case LV_EVENT_SHORT_CLICKED:
Serial.printf("Short clicked\n");
break;
case LV_EVENT_CLICKED:
Serial.printf("Clicked\n");
break;
case LV_EVENT_LONG_PRESSED:
Serial.printf("Long press\n");
break;
case LV_EVENT_LONG_PRESSED_REPEAT:
Serial.printf("Long press repeat\n");
break;
case LV_EVENT_RELEASED:
Serial.printf("Released\n");
break;
}
}
void setup() {
Serial.begin(115200);
while (!Serial && millis() < 2000) {} //wait up to 2 seconds for Serial Monitor to connect
Serial.println("RA8876 LvGL test starting!");
Serial.print("Compiled ");
Serial.print(__DATE__);
Serial.print(" at ");
Serial.println(__TIME__);
//I'm guessing most copies of this display are using external PWM
//backlight control instead of the internal RA8876 PWM.
//Connect a Teensy pin to pin 14 on the display.
//Can use analogWrite() but I suggest you increase the PWM frequency first so it doesn't sing.
pinMode(BACKLITE, OUTPUT);
digitalWrite(BACKLITE, HIGH);
pinMode(LED_PIN, OUTPUT);
lv_init();
tft.begin(); // TFT init
cts.begin(); //capacative touchscreen init
lv_disp_buf_init(&disp_buf, buf_1, buf_2, BUFFER_SIZE);
//Initialize the display driver - basically just the buffers
lv_disp_drv_t disp_drv;
lv_disp_drv_init(&disp_drv);
disp_drv.hor_res = screenWidth;
disp_drv.ver_res = screenHeight;
disp_drv.flush_cb = my_disp_flush;
disp_drv.buffer = &disp_buf;
lv_disp_drv_register(&disp_drv);
//initialize the input device driver
lv_indev_drv_t indev_drv;
lv_indev_drv_init(&indev_drv); /*Descriptor of a input device driver*/
indev_drv.type = LV_INDEV_TYPE_POINTER; /*Touch pad is a pointer-like device*/
indev_drv.read_cb = my_touchpad_read; /*Set your driver function*/
lv_indev_drv_register(&indev_drv); /*Finally register the driver*/
//start the 1ms callback, so that LvGL can run its animations
MsTimer2::set(LVGL_TICK_PERIOD, myTick);
MsTimer2::start();
//Configure EventResponder to run as immediately as possible in an interrupt when SPI DMA finishes
spiDMAEvent.attachImmediate(spiEventResponder);
//Set the theme.. NOTE THEMES MUST BE ENABLED INDIVIDUALLY IN lv_conf.h
//lv_theme_t * th = lv_theme_night_init(210, NULL); //Set a HUE value and a Font for the Night Theme
lv_theme_t * th = lv_theme_alien_init(10, NULL); //Set a HUE value and a Font for the Alien Theme
lv_theme_set_current(th);
lv_obj_t * scr = lv_cont_create(NULL, NULL);
lv_disp_load_scr(scr);
/* Create simple label */
lv_obj_t *label = lv_label_create(lv_scr_act(), NULL);
lv_label_set_text(label, "LED DIMMER");
lv_obj_align(label, NULL, LV_ALIGN_CENTER, 0, -50);
/* Create a slider in the center of the display */
lv_obj_t * slider = lv_slider_create(lv_scr_act(), NULL);
lv_obj_set_width(slider, screenWidth - 50); /*Set the width*/
lv_obj_set_height(slider, 50);
lv_obj_align(slider, NULL, LV_ALIGN_CENTER, 0, 0); /*Align to the center of the parent (screen)*/
lv_obj_set_event_cb(slider, slider_event_cb); /*Assign an event function*/
/* Create a label below the slider */
slider_label = lv_label_create(lv_scr_act(), NULL);
lv_label_set_text(slider_label, "0");
lv_obj_set_auto_realign(slider, true);
lv_obj_align(slider_label, slider, LV_ALIGN_OUT_BOTTOM_MID, 0, 10);
}
void loop() {
lv_task_handler(); /* let the GUI do its work */
delay(3);
}
mjs513
Senior Member+
Already on the list but keep getting side tracked
Besides with all the other rework wanted to make sure everything else worked first
mjs513
Senior Member+
Just to update all, I was able to get rotated text to appear on the screen. Sadly, doing so requires flipping the Vertical Scan Direction (Bottom to Top). Sadly, this disables PIP. It also makes me you think harder about writing graphics as the variables defined as TBLR, LRTB, etc. are now backwards from their acronym. I also had to build a custom function in the library that prints one character at a time and then resets the cursor in the x direction and moves it in the y direction - so the x and y axis are still oriented to the screen the same way, though y now moves from bottom to top as opposed to top to bottom. There may be a better way to build these functions - a programmer I am not - but I have copied below what I added to the library should this help others in the future. Also, in figuring this out, I discovered (again I very well could be wrong) that the initialization in lines 226 and 227 of Ra8876_Lite.cpp (called out as TFT timing configure) do not appear to be recognized (or they are being overwritten).
What I added for text rotation...
What I added for text rotation...
Code:
//**************************************************************//
/* JB ADD FOR ROTATING TEXT */
/* Turn RA8876 text rotate mode ON/OFF (True = ON) */
//**************************************************************//
void Ra8876_Lite::textRotate(boolean on)
{
if(on)
{
lcdRegDataWrite(RA8876_CCR1, RA8876_TEXT_ROTATION<<4);//cdh
}
else
{
lcdRegDataWrite(RA8876_CCR1, RA8876_TEXT_NO_ROTATION<<4);//cdh
}
}
//**************************************************************//
/* JB ADD FOR ROTATING Image */
/* Turn RA8876 image rotate mode ON/OFF (True = ON) */
//**************************************************************//
void Ra8876_Lite::imageRotate(boolean on)
{
if(on)
lcdRegDataWrite(RA8876_MACR, RA8876_WRITE_MEMORY_TBLR<<1);//02h
else
lcdRegDataWrite(RA8876_MACR, RA8876_WRITE_MEMORY_LRTB<<1);//02h
}
//**************************************************************//
/* JB ADD FOR printing rotated strings */
//**************************************************************//
void Ra8876_Lite::rotatePrint(ru16 x0,ru16 y0, const char *str)
{
textMode(true);
textRotate(true);
while(*str != '\0')
{
setTextCursor(x0, y0);//added 16 May 2020 to place strings in the correct location
write(*str);
++str;
y0 = y0 + _FNTwidth;
}
textRotate(false);
}
//**************************************************************//
/* JB ADD for having the screen write from the bottom up */
/* Puts y = 0 at the bottom, allowing for text flip... */
//**************************************************************//
void Ra8876_Lite::bottomUp(boolean on)
{
if(on)
lcdRegDataWrite(RA8876_DPCR,
XPCLK_INV<<7|RA8876_DISPLAY_ON<<6|RA8876_VDIR_BT<<3|RA8876_OUTPUT_RGB<<0);
else
lcdRegDataWrite(RA8876_DPCR,
XPCLK_INV<<7|RA8876_DISPLAY_ON<<6|RA8876_VDIR_TB<<3|RA8876_OUTPUT_RGB<<0);
}
Last edited:
wwatson
Well-known member
Nice work. And it is a start. This display controller and the RA8875 are not easy to work with.One of the things that I remember Sumotoy was working on with his RA8875 display driver was bit mapped text characters. He was trying to optimize it using several algorithms he was working on. It's going to take time, talent and programming skills to work these things out. You and @mjs513 have accomplished so much from reworking my simple attempt at modifying the original Ra8876_Lite driver. I really wish it was easier to understand the ref manual
But HEY that's typical. Right now I really want to finish up working with MSC and move on to working with this and other new adventures with the Teensys. My programming skills are getting better as I learn, but far below the standard of this forum.You and @mjs513 have it going on. Can't wait to see what happens when @KurtE gets his display as well
KurtE
Senior Member+
It arrived yesterdayYou and @mjs513 have it going on. Can't wait to see what happens when @KurtE gets his display as well
Still need to hook it up. I do have a board that I started to do for the RA8875, which I started to assemble and found some issues and some of the IO pins appeared to not work...
But then figured out that the 1x11 connector object for those pins was accidentally rotated 180 degrees in the layout program. So the pins worked just they were not in the order I expected and I had on the silk screen. So maybe I should go ahead and put on the connector for display...
dauntless89
Well-known member
wwatson, do you have any experience with this device in outdoor lighting conditions?
This type of display would fit my bill for an integrated instrumentation system in an automotive application, but the 100 cd/m2 the datasheet calls out has me concerned about readability.
This type of display would fit my bill for an integrated instrumentation system in an automotive application, but the 100 cd/m2 the datasheet calls out has me concerned about readability.
KurtE
Senior Member+
Quick update - I finished assembling the basics of my RA8875 kitchen sink board, and plugged in RA8875 and it works with T4.1 I cut the VIN/VSB and have jumper on board to either run from USB or +5v connector... Works with RA8875
Updated my RA8876 stuff with @mjs513 rewrite branch. Found several examples did not compile, but memory transfer does. I plugged in the RA8876 (modified for RST=9 not 8.
Runs:
But nothing on display.
Looking at code it appears it is expecting to use external PWM for backlight... Question is, do I need to run a jumper over to that pin (currently floating) or has anyone figured out the settings to use the internal boards PWM?
I cut the VIN/VSB and have jumper on board to either run from USB or +5v connector... Works with RA8875 Updated my RA8876 stuff with @mjs513 rewrite branch. Found several examples did not compile, but memory transfer does. I plugged in the RA8876 (modified for RST=9 not 8.
Runs:
Code:
LCD Memory Transfer test starting!
Compiled May 28 2020 at 14:33:58
SPI transfer speed 5.0MHz
fillRect operation takes 0.675 milliseconds to fill the image area.
Put-picture from PROGMEM to display took 0.228ms to begin the operation.
But the next LCD operation was delayed by 101.808ms because data transfer was still underway
Copy from PROGMEM to display took 0.227ms to begin the transfer (data is on its way while you read this.)
16-bit copy from PROGMEM to display took 104.011ms
Chromakey copy from PROGMEM to display took 101.252ms to run to completion.
ROP 15 BTE copy took 0.280ms, followed by 0.783ms internal processing in the RAiO chip.
ROP 0 BTE copy took 0.280ms, followed by 0.784ms internal processing in the RAiO chip.
ROP 1 BTE copy took 0.280ms, followed by 1.779ms internal processing in the RAiO chip.
ROP 2 BTE copy took 0.279ms, followed by 2.139ms internal processing in the RAiO chip.
ROP 3 BTE copy took 0.279ms, followed by 1.288ms internal processing in the RAiO chip.
ROP 4 BTE copy took 0.281ms, followed by 2.152ms internal processing in the RAiO chip.
ROP 5 BTE copy took 0.279ms, followed by 1.118ms internal processing in the RAiO chip.
ROP 6 BTE copy took 0.279ms, followed by 2.172ms internal processing in the RAiO chip.
ROP 7 BTE copy took 0.280ms, followed by 2.137ms internal processing in the RAiO chip.
ROP 8 BTE copy took 0.279ms, followed by 1.497ms internal processing in the RAiO chip.
ROP 9 BTE copy took 0.280ms, followed by 2.160ms internal processing in the RAiO chip.
ROP 10 BTE copy took 0.279ms, followed by 1.124ms internal processing in the RAiO chip.
ROP 11 BTE copy took 0.280ms, followed by 2.147ms internal processing in the RAiO chip.
ROP 12 BTE copy took 0.280ms, followed by 1.341ms internal processing in the RAiO chip.
ROP 13 BTE copy took 0.279ms, followed by 2.138ms internal processing in the RAiO chip.
ROP 14 BTE copy took 0.281ms, followed by 1.991ms internal processing in the RAiO chip.
First Page Finished, PRESS ANY KEY...
Test Alpha...Looking at code it appears it is expecting to use external PWM for backlight... Question is, do I need to run a jumper over to that pin (currently floating) or has anyone figured out the settings to use the internal boards PWM?
mjs513
Senior Member+
@KurtE
The examples we have been working with has just been connecting the backlight pin to the T4.1 and doing:
Don't think we have played with using PWM?
Guess I am going to have to pull out the 8876 and start playing with it again
The examples we have been working with has just been connecting the backlight pin to the T4.1 and doing:
Code:
pinMode(BL Pin, OUTPUT);
digitalWrite(BL Pin, HIGH);Don't think we have played with using PWM?
Guess I am going to have to pull out the 8876 and start playing with it again
wwatson
Well-known member
@KurtE
The examples we have been working with has just been connecting the backlight pin to the T4.1 and doing:
Code:pinMode(BL Pin, OUTPUT); digitalWrite(BL Pin, HIGH);
Don't think we have played with using PWM?
Guess I am going to have to pull out the 8876 and start playing with it again
I had the same problem. In setup:
Code:
//I'm guessing most copies of this display are using external PWM
//backlight control instead of the internal RA8876 PWM.
//Connect a Teensy pin to pin 14 on the display.
//Can use analogWrite() but I suggest you increase the PWM frequency first so it doesn't sing.
pinMode(BACKLITE, OUTPUT);
analogWriteFrequency(BACKLITE, 1000000);
//digitalWrite(BACKLITE, HIGH);
analogWrite(BACKLITE, 256);I had to change to digitalWrite() and comment out both analogWrite..() lines. have not figured that one out yet.
Edit: Sorry. Replied to the wrong post
Last edited:
wwatson
Well-known member
Yep. Me to. I think the display draws to much current for the Teensy to supply. I have never actually measured it but I know that with using the USB host port it's not enough. Again I think that is what killed my first display.
Edit: It is not the Teensy but the PC USB port that does not supply enough current. (I am using the 5V version of the display)
Last edited:
wwatson
Well-known member
To be honest I have not. It is very readable with all my lights on including the maglite hanging over it in my little cave but I have never had it exposed outside in the sunlight.
defragster
Senior Member+
KurtE are you using external power or all over USB?
KurtE
Senior Member+
I have tried both and I now get the display working but as I mentioned USB does not want to talk to PC...
Probably what I should do is to try to power the display separately.
Note: When I tried it using USB, it is off my powered hub, no PC complaints, but maybe internal to HUB shuts off communication.
External power is from wall wart that outputs 5v at 4 amps...
Will try more soon.