Hi,
I have an arduino Nano with a Heltec (similar to Waveshare) 1.54" e-ink display. Im trying to figure out a way to have numerous lines of text, then partially update 1 line to something else without disturbing the other lines.
a a
b b
c --> C
d d
Partial update code:
// : 1.54inch e-paper display demo
#include <SPI.h>
#include <EPD1in54.h>
#include <EPDPaint.h>
#include "imagedata.h"
#define COLORED 0
#define UNCOLORED 1
/**
* Due to RAM not enough in Arduino UNO, a frame buffer is not allowed.
* In this case, a smaller image buffer is allocated and you have to
* update a partial display several times.
* 1 byte = 8 pixels, therefore you have to set 8*N pixels at a time.
*/
unsigned char image[1024];
EPDPaint paint(image, 0, 0); // width should be the multiple of 8
EPD1in54 epd; // default reset: 8, dc: 9, cs: 10, busy: 7
unsigned long timeStartMs;
unsigned long timeNowS;
unsigned long timeShowedS = 1000;
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
if (epd.init(lutFullUpdate) != 0) {
Serial.print("e-Paper init failed");
return;
}
/**
* there are 2 memory areas embedded in the e-paper display
* and once the display is refreshed, the memory area will be auto-toggled,
* i.e. the next action of SetFrameMemory will set the other memory area
* therefore you have to clear the frame memory twice.
*/
epd.clearFrameMemory(0xFF); // bit set = white, bit reset = black
epd.displayFrame();
epd.clearFrameMemory(0xFF); // bit set = white, bit reset = black
epd.displayFrame();
if (epd.init(lutPartialUpdate) != 0) {
Serial.print("e-Paper init failed");
return;
}
epd.setFrameMemory(IMAGE_DATA);
epd.displayFrame();
epd.setFrameMemory(IMAGE_DATA);
epd.displayFrame();
timeStartMs = millis();
}
void loop() {
// put your main code here, to run repeatedly:
timeNowS = (millis() - timeStartMs) / 1000;
if (timeNowS != timeShowedS) {
timeShowedS = timeNowS;
updateTime(timeShowedS);
}
delay(20);
}
void updateTime(unsigned long seconds) {
char time_string[] = {'0', '0', ':', '0', '0', '\0'};
time_string[0] = seconds / 60 / 10 + '0';
time_string[1] = seconds / 60 % 10 + '0';
time_string[3] = seconds % 60 / 10 + '0';
time_string[4] = seconds % 60 % 10 + '0';
paint.setWidth(40);
paint.setHeight(96);
paint.setRotate(ROTATE_270);
paint.clear(UNCOLORED);
paint.drawStringAt(0, 4, time_string, &Font24, COLORED);
epd.setFrameMemory(paint.getImage(), 88, 88, paint.getWidth(), paint.getHeight());
epd.displayFrame();
}
This code uses a picture file, displays it then in the gap partially updates the screen with a timer.
The next code is the same, but displaying a line of text, then hoping to display the same timer underneath it and have it partially updating. Problem is each time the timer updates so does the entire screen. I am not sure why...
// : 1.54inch e-paper display demo
#include <SPI.h>
#include <EPD1in54.h>
#include <EPDPaint.h>
#include "imagedata.h"
#define COLORED 0
#define UNCOLORED 1
/**
* Due to RAM not enough in Arduino UNO, a frame buffer is not allowed.
* In this case, a smaller image buffer is allocated and you have to
* update a partial display several times.
* 1 byte = 8 pixels, therefore you have to set 8*N pixels at a time.
*/
unsigned char image[1024];
EPDPaint paint(image, 0, 0); // width should be the multiple of 8
EPD1in54 epd; // default reset: 8, dc: 9, cs: 10, busy: 7
unsigned long timeStartMs;
unsigned long timeNowS;
unsigned long timeShowedS = 1000;
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
if (epd.init(lutFullUpdate) != 0) {
Serial.print("e-Paper init failed");
return;
}
epd.clearFrameMemory(0xFF); // bit set = white, bit reset = black
epd.displayFrame();
epd.clearFrameMemory(0xFF); // bit set = white, bit reset = black
epd.displayFrame();
paint.setRotate(ROTATE_0);
paint.setWidth(200);
paint.setHeight(24);
paint.clear(UNCOLORED);
paint.drawStringAt(30, 4, "TESTING", &Font16, COLORED);
epd.setFrameMemory(paint.getImage(), 0, 10, paint.getWidth(), paint.getHeight());
epd.displayFrame();
delay(2000); //Partial update next
timeStartMs = millis();
}
void loop() {
// put your main code here, to run repeatedly:
timeNowS = (millis() - timeStartMs) / 1000;
if (timeNowS != timeShowedS) {
timeShowedS = timeNowS;
updateTime(timeShowedS);
}
delay(20);
}
void updateTime(unsigned long seconds) {
char time_string[] = {'0', '0', ':', '0', '0', '\0'};
time_string[0] = seconds / 60 / 10 + '0';
time_string[1] = seconds / 60 % 10 + '0';
time_string[3] = seconds % 60 / 10 + '0';
time_string[4] = seconds % 60 % 10 + '0';
paint.setWidth(200);
paint.setHeight(32);
paint.setRotate(ROTATE_0);
paint.clear(UNCOLORED);
paint.drawStringAt(0, 4, time_string, &Font24, COLORED);
epd.setFrameMemory(paint.getImage(), 40, 80, paint.getWidth(), paint.getHeight());
epd.displayFrame();
}
Any help would be greatly received, yes I am aware of the dangers of running 5v pins to the display but seems ok so far.
Many thanks. J.
imagedata.cpp (26.2 KB)
imagedata.h (1.24 KB)