A communication exception may occur when the serial port is used

[ShiPC123]

Hello, when I use the serial port to modify the displayed content, I find that there is a certain probability that the serial port command will not respond to the situation, I suspect that the timer is interrupted to cause the abnormal serial communication, is there a way to temporarily disable the timer interrupt

[board707]

Hi
Please describe your setup - what is the board you use, which and how many panels are connected?
What the version of the library do you use?

[ShiPC123]

Hello ,i use the stm32f103RCT6 and connect one panel ,I just updated the latest version of the library file and it seems that the problem has been solved
this is my code:

#include "DMD_RGB.h"
#define DISPLAYS_ACROSS 1
#define DISPLAYS_DOWN 1

#define ENABLE_DUAL_BUFFER false

// ==== DMD_RGB pins ====
// mux pins - A, B, C... all mux pins must be selected from same port!
#define DMD_PIN_A PB15
#define DMD_PIN_B PB14
#define DMD_PIN_C PB13
#define DMD_PIN_D PB12
#define DMD_PIN_E PB5
// put all mux pins at list
uint8_t mux_list[] = { DMD_PIN_A , DMD_PIN_B , DMD_PIN_C , DMD_PIN_D , DMD_PIN_E };

// pin OE must be one of PB0 PB1 PA6 PA7
#define DMD_PIN_nOE PB0
#define DMD_PIN_SCLK PB1

uint8_t custom_rgbpins[] = {PA0, PA1, PA2, PA3, PA4, PA5, PA6}; // CLK, R0, G0, B0, R1, G1, B1

#define RGB80x40_S10 3,80,40,10,102,4,PATTERN_UPS

DMD_RGB_SHIFTREG_ABC <RGB80x40_S10, COLOR_4BITS_Packed> dmd(mux_list, DMD_PIN_nOE, DMD_PIN_SCLK, custom_rgbpins, DISPLAYS_ACROSS, DISPLAYS_DOWN, ENABLE_DUAL_BUFFER);

uint16_t bg = 0; // background - black
uint16_t fg_r = 0; // foreground
uint16_t fg_g = 0; // foreground
uint16_t fg_b = 0; // foreground
uint16_t now_fg;
uint8_t num_val;

unsigned char receive_buffer[30]; //保存接收数据
unsigned char send_buffer[30]; //保存接收数据

#define led_run_pin PC7
bool need_updata = 0;

void setup(void)
{
delay(2000);
Serial4.begin(115200);
Serial1.begin(115200);
// uncomment the line below if you using St-Link with STM32F103xx boards
dmd.init();
//enableDebugPorts();

fg_r = dmd.Color888(255, 0, 0);
fg_g = dmd.Color888(0, 255, 0);
fg_b = dmd.Color888(0, 0, 255);
dmd.setBrightness(5);
}

void loop(void) {
uart_receive();
if (need_updata == 1) {
dmd.fillScreen(bg);
for (int i = 0; i < dmd.height(); i++) {
for (int j = 0; j < dmd.width(); j++) {
dmd.drawPixel(j, i, now_fg);
//delay(3);
}
}
need_updata = 0;
}
}

void uart_receive() {
unsigned int characterTime = 750;
unsigned char address = 0;
while (Serial4.available() > 0) //如果串口缓冲区数据量大于0进入条件
{
if (address < 255)
{
receive_buffer[address] = Serial4.read();
address++;
}
else //条件不满足时直接清空缓冲区
{
Serial4.read();
}
delayMicroseconds(characterTime); //等待1.5个字符时间
if (Serial4.available() == 0) //1.5个字符时间后缓冲区仍然没有收到数据,认为一帧数据已经接收完成,进入条件
{
if (receive_buffer[0] == 0xAA && receive_buffer[1] == 0x55 && receive_buffer[2] == 0x02) {
switch (receive_buffer[3]) {
case 0x01:
now_fg = fg_g;
break;
case 0x02:
now_fg = fg_r;
break;
}
if (receive_buffer[4] >= 0 && receive_buffer[4] <= 9) {
num_val = receive_buffer[4];
}
need_updata = 1;
}
}
}
}

[board707]

problem has been solved

You are welcome :)

[ShiPC123]

My last version of the library was v1.1.2. Did you fix any bugs? So far in my tests, the problem has not recurred

[board707]

Did you fix any bugs?

I don't think I fixed anything that would be relevant to your problems.
A full changes log you can see in
https://github.com/board707/DMD_STM32/blob/dev-V2/CHANGES.txt

[ShiPC123]

Thank you very much, if I use the V1.1.2 version of the library file, there will often be a serial port data receiving error, but I updated to the latest version, the fault disappeared, I will use the latest version of the library file, thank you

[board707]

Thank you for your feedback.
Could you please describe the error in more details?

[ShiPC123]

I use this code to process the serial port data, which is used to change the display color and text, but if I set the baud rate of the serial port to 115200 or higher, I often find that the serial port data cannot be received. If I lower the baud rate to 9600, for example, the probability of failure will be reduced. Serial port I use serial port 4 (PC10 and PC11)

void uart_receive() {
unsigned int characterTime = 750;
unsigned char address = 0;
while (Serial4.available() > 0)
{
if (address < 255)
{
receive_buffer[address] = Serial4.read();
address++;
}
else
{
Serial4.read();
}
delayMicroseconds(characterTime);
if (Serial4.available() == 0)
{
if (receive_buffer[0] == 0xAA && receive_buffer[1] == 0x55 && receive_buffer[2] == 0x02) {
switch (receive_buffer[3]) {
case 0x01:
now_fg = fg_g;
break;
case 0x02:
now_fg = fg_r;
break;
}
if (receive_buffer[4] >= 0 && receive_buffer[4] <= 9) {
num_val = receive_buffer[4];
}
need_updata = 1;
}
}
}
}

[ShiPC123]

Sorry, the failed library version is V1.1.4 instead of V1.1.2

[ShiPC123]

Hello today I tested the scroll display, if the baud rate is set to 115200, there will be incomplete data reception, in addition, whether there is a way to improve the scroll speed

[ShiPC123]

651487c1d6f631e2edb93b0167457400.mp4

The interval in this video is 20 but the scrolling is a little slow, is there any way to increase the scrolling speed

[ShiPC123]

This is my entire code file

/*--------------------------------------------------------------------------------------
Demo for RGB panels

DMD_STM32a example code for STM32F103xxx board
------------------------------------------------------------------------------------- */
#include "DMD_RGB.h"

// Fonts includes
#include "MyFont.h"

#pragma GCC diagnostic ignored "-Wnarrowing"
#pragma GCC diagnostic ignored "-Woverflow"
//#include "gfx_fonts/Jigmo324pt7b.h"
//#include "gfx_fonts/FreeMono12pt7b.h"
#pragma GCC diagnostic warning "-Wnarrowing"
#pragma GCC diagnostic warning "-Woverflow"

//Number of panels in x and y axis

#define DISPLAYS_ACROSS 3
#define DISPLAYS_DOWN 1

// Enable of output buffering
// if true, changes only outputs to matrix after
// swapBuffers(true) command
// If dual buffer not enabled, all output draw at matrix directly
// and swapBuffers(true) cimmand do nothing
#define ENABLE_DUAL_BUFFER true

// ==== DMD_RGB pins ====
// mux pins - A, B, C... all mux pins must be selected from same port!
#define DMD_PIN_A PB15
#define DMD_PIN_B PB14
#define DMD_PIN_C PB13
#define DMD_PIN_D PB12
#define DMD_PIN_E PB5
// put all mux pins at list
uint8_t mux_list[] = { DMD_PIN_A , DMD_PIN_B , DMD_PIN_C , DMD_PIN_D };

// pin OE must be one of PB0 PB1 PA6 PA7
#define DMD_PIN_nOE PB0
#define DMD_PIN_SCLK PB1

// Pins for R0, G0, B0, R1, G1, B1 channels and for clock.
// By default the library uses RGB color order.
// If you need to change this - reorder the R0, G0, B0, R1, G1, B1 pins.
// All this pins also must be selected from same port!
uint8_t custom_rgbpins[] = { PA0, PA1, PA2, PA3, PA4, PA5, PA6 }; // CLK, R0, G0, B0, R1, G1, B1

// Fire up the DMD object as dmd<MATRIX_TYPE, COLOR_DEPTH>
// We use 64x32 matrix with 16 scans and 4bit color:
#define RGB80x40_s10 3,80,40,10,102,4,PATTERN_UPS
DMD_RGB_SHIFTREG_ABC <RGB80x40_s10, COLOR_4BITS_Packed> dmd(mux_list, DMD_PIN_nOE, DMD_PIN_SCLK, custom_rgbpins, DISPLAYS_ACROSS, DISPLAYS_DOWN, ENABLE_DUAL_BUFFER);

// --- Define fonts ----
// DMD.h old style font
DMD_Standard_Font MyFont24(System24x48);

char str_recive[100];
char* m;
bool need_updata = 0;

unsigned char receive_buffer[100];
unsigned char send_buffer[100];

void setup(void)
{

delay(500);
Serial4.begin(38400);
Serial1.begin(115200);
dmd.init(3000);

}

void loop(void)
{

// create foreground colors
uint16_t col[] = {
dmd.Color333(255, 0, 0), // red
dmd.Color333(0, 255, 0), // green
dmd.Color333(0, 0, 255) // blue

};
uint16_t bg = 0; // background - black
int col_cnt = 3; // color count

dmd.selectFont(&MyFont24);

// set text foreground and background colors
dmd.setTextColor(col[0], bg);

// shift steps in pixels for running text (positive - shift right, negative - left)
// running text shift interval
uint16_t interval = 20;

long prev_step = millis();
uint8_t col_ptr = 0;
uint8_t i = 0, b = 0;
dmd.setBrightness(80);
int x = dmd.width() - 1;
dmd.setTextColor(col[0], bg);

// Cycle for tests:
// -- running texts moving at x and y axis with single and double speed
// -- vertical scrolling message
while (1) {
uart_receive();
if (need_updata == 1) {
need_updata = 0;
m = str_recive;
}

if ((millis() - prev_step) > interval) {
  prev_step = millis();  // moved to the start of the loop to prevent "scroll not smooth" issue
  x--;
  if (x < -1 * dmd.stringWidth(m))
  {
    x = dmd.width() - 1;
  }

}

dmd.drawMarqueeX(m, x, -4);
dmd.swapBuffers(false);

}
}

void uart_receive() {
unsigned int characterTime = 750;
unsigned char address = 0;
while (Serial4.available() > 0)
{
if (address < 255)
{
receive_buffer[address] = Serial4.read();
address++;
}
else
{
Serial4.read();
}
delayMicroseconds(characterTime);
if (Serial4.available() == 0)
if (receive_buffer[0] == 0xAA && receive_buffer[1] == 0x55 && receive_buffer[2] == 0x02) {
for (int i = 0; i < receive_buffer[3]; i++) {
str_recive[i] = receive_buffer[4 + i];
}
need_updata = 1;
}
}
}
}

[board707]

Could you attach a zip archive with your code and font files (and any others files, if you use them in project) to able me to test the code myself?

[ShiPC123]

DEGUG.zip

[board707]

Thanks
I will test it

[board707]

@ShiPC123
I looked at your code and ran it on my STM32F103RE board.
First of all, your code contains several errors, including one quite serious - when you receive text from the port, you read more symbols into receive buffer than the memory allocated there. There are other errors, if necessary, I can tell you in detail.

However, all the errors are not related to the main problem - that the output to the matrix works very slowly. It is the reason that changing the interval parameter does not affect the scrolling speed - it is because a single matrix update takes much more than 20ms.

Partially, this is explained by the fact that your board is weak for such a screen - you have three fairly large panels, and they also have a complex pixel layout. However, I tried your code on faster boards - such as STM32f4 or Raspberry RP2040 - and although they work several times faster, the speed is still very low.
Perhaps we found some kind of bug in the library. But I can't say for sure yet, I'll probably have to run more complex tests, it will take a few days

[ShiPC123]

Thanks for your hard work.

[board707]

Hi
Over the weekend I did some testing and it turns out that the problem is more serious than I thought. The fact that the panels are updating slowly is not some isolated bug, but is due to the general design of the library.
This has not occurred for me until now, because in other projects users usually update only a small part of the screen. In your case, you are working with a very large font, where the text actually takes up the entire screen. Add to this the fact that your panels have a non-standard structure - that is, in your case, you cannot move pixels around the screen to create a running line - the text has to be redrawn each time.
I will continue to deal with this problem, but it is unlikely that a solution will appear in the next few days. In order for the text on your screen to move smoothly, the library code must be sped up by about 10 times, which is quite unlikely.
Perhaps you should look for another library.