Adding a flush and delay makes this program work as expected now. A byte is written on the TX pin every 100 ms.

#include <HardwareSerial.h>
uint8_t a= 10;
HardwareSerial MySerial(1);

void setup() {
pinMode(10, OUTPUT);
}

void loop() {
MySerial.begin(250000, SERIAL_8N1, 9, 10);
MySerial.write ...

I tried changing the code to use HardwareSerial specifically but the results are the same.

#include <HardwareSerial.h>
uint8_t a= 10;
HardwareSerial MySerial(1);

void setup() {
}

void loop() {
MySerial.begin(250000, SERIAL_8N1, 9, 10);
MySerial.write(a);
MySerial.end();
//MAKE PIN 10 GENERAL ...

I wrote program to begin serial 1, send a byte then disable serial1 and loop. If Serial1.end() is called then the TX pin will not function properly. The first time loop() runs it send the byte then stays low for about 600 microseconds and stays high after that. The TX channel stops toggling after ...

Here is all the code, basically the SD_Test example

#include "FS.h"
#include "SD.h"
#include "SPI.h"

void listDir(fs::FS &fs, const char * dirname, uint8_t levels){
Serial.printf("Listing directory: %s\n", dirname);

File root = fs.open(dirname);
if(!root){
Serial.println("Failed to open ...

Hi All

Using the SD library (not SD MMC), if I have the SD card in and start the ESP32 then the card is recognized. If I take out the card and put it back in seconds later, it will not be recognized again.

if(!SD.begin(cs, SPI, freq))
this will fail.

Has any one seen this before? Does the SD ...

Scope shows there is no activity on SCK during the hang.
Is it maybe something in the "fs" library?

I want to connect a SD card on VSPI and also connect a LCD on the same pin for MISO, MOSI, SCK. The 2 CS pins are connected on different ESP pins so that I can control which device the SPI is talking to.

The SD card example included with the ESP32 core hangs after LCD commands.
cardSize = SD ...

What exactly happens when it reboots? If allocating 115200 bytes fails then the assert() will fail, and the ESP32 will print an error message and reset. This means there wasn't enough free heap (in a single contiguous block) to allocate 115200 bytes. Maybe there is enough to make 2-3 smaller ...

I have the same problem with large arrays and heap limitations.
heap_caps_get_largest_free_block(8) returns 113K bytes and ESP.getFreeHeap() returns 285K bytes.


Because blocks are not contiguous, the maximum size you will be able to allocate from the heap will always be smaller than the value ...

Now I tried 2 arrays with half the size each in case the compiler doesnt like one large memory allocation but it doesnt compile either
uint8_t arrA[57600];
uint8_t arrB[57600];

float arrF[768];
uint8_t arr2[768];
uint8_t arr3[768];
uint16_t arr4[850];


void setup() {
Serial.begin(250000 ...