#001 ESP32 UART0,1,2 with arduino IDE

I am following Mr. accent swiss' utube for ESP32 learning.

I have update the ESP8266 support to 2.4 and the ESP32 support with latest json file as he mentioned in the film:



I'm interested in multi-UART usage, I learned that there are 3 uarts on ESP32, one is used by USB for debugging, and Serial2 should be on IO16(RX) and IO17(TX), Serial1 is using IO12/IO13, according to his #152 video, IO12 is used internally for flash stuff, so if you try to use :
HardwareSerial2(2) the the processor will crash.
So I wish to do a test on it, I copied:

HardwareSerial Serial1(1);
HardwareSerial Serial2(2);
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
Serial1.begin(115200);
Serial2.begin(115200);

}
void loop() {
Serial.println("This message sent to USB serial");
Serial1.println("This message sent to UART1 serial1");
Serial2.println("This message sent to UART2 serial2");
delay(1000);
}

I down loaded to my wemos OLED ESP32, and it did not crash...
According to the pin out I got from http://www.instructables.com/id/ESP32-With-Integrated-OLED-WEMOSLolin-Getting-Star/
the RX/TX marked on my board is actually Rx0/Tx0 which is the same as USB one.

which is consist with what I got on arduino monitor and the docklight with FTDI connected to RX/TX pins on board.                                                  
       
                                                                                                                                                                           

 









  
This surprised me, since the video is dated 2017 Oct, and it's corrected. I think there must be some change on the pin define, since ESP32 has very good pin muxing capability. according to the video, this is done with
\hardware\espressif\esp32\cores\esp32\HardwareSerial.cpp

So I find and open it and find in hardware serial.begin

void HardwareSerial::begin(unsigned long baud, uint32_t config, int8_t rxPin, int8_t txPin, bool invert)
{
    if(0 > _uart_nr || _uart_nr > 2) {
        log_e("Serial number is invalid, please use 0, 1 or 2");
        return;
    }
    if(_uart) {
        end();
    }
    if(_uart_nr == 0 && rxPin < 0 && txPin < 0) {
        rxPin = 3;
        txPin = 1;
    }
    if(_uart_nr == 1 && rxPin < 0 && txPin < 0) {
        rxPin = 9;
        txPin = 10;
    }
    if(_uart_nr == 2 && rxPin < 0 && txPin < 0) {
        rxPin = 16;
        txPin = 17;
    }
    _uart = uartBegin(_uart_nr, baud, config, rxPin, txPin, 256, invert);
}

But I have no intention to change the pin define in the lib. in the messaging of the video, there is one example:
HardwareSerial Serial1(1); HardwareSerial Serial2(2); #define TX1_pin 12 #define RX1_pin 13 #define TX2_pin 2 #define RX2_pin 4 void setup() { Serial.begin(115200); Serial1.begin(115200, SERIAL_8N1, RX1_pin, TX1_pin); Serial2.begin(115200, SERIAL_8N1, RX2_pin, TX2_pin); } void loop() { Serial.println("This message is sent to USB Seriall"); Serial1.println("This message is sent to UART1 Serial"); Serial2.println("This message is sent to UART2 Serial"); delay(1000); }

According to the pinout of my little wemos OLED, I make it as:

HardwareSerial Serial1(1); HardwareSerial Serial2(2); #define TX1_pin 15 #define RX1_pin 16 #define TX2_pin 2 #define RX2_pin 4 void setup() { // put your setup code here, to run once: Serial.begin(115200); Serial1.begin(115200, SERIAL_8N1, RX1_pin, TX1_pin); Serial2.begin(115200, SERIAL_8N1, RX2_pin, TX2_pin);

And it finally works....


I did not understand why the original one did not crash, as saying that io9 and io10 is used for flash...

Here is another very good program for using3 uarts mapping to 3 UDP port.
https://github.com/AlphaLima/ESP32-Serial-Bridge

So, currently I wish to use following pin muxing:
on uart 1

//#define RX1_pin  2// with this config RX=2, TX=4, I can't load the code with FTDI connected
//#define TX1_pin  4
#define RX1_pin  4// with this config Rx=4, Tx=2, I can load the code with FTDI connected
#define TX1_pin  2
HardwareSerial Serial2(2);
#define RX2_pin  14
#define TX2_pin  16


I think that's some thing about how ESP32 access it's flash when boot up....

留言

張貼留言

這個網誌中的熱門文章

Heltec ESP32+OLED+Lora, hardware testing

圖片
you can easily find some good boards from china, but most of them lack of accurate document... Hrere is an example; https://hackaday.io/project/26991-esp32-board-wifi-lora-32 the board looks good with lora and a 128x64 OLED, but the IIC and reset connection is important, since pin can be muxing easily, so every board could be different. pinMode(16,OUTPUT);  digitalWrite(16, LOW); // set GPIO16 low to reset OLED  delay(50);  digitalWrite(16, HIGH); // while OLED is running, must set GPIO16 to high  and, if needed, edit your Wire.begin() to Wire.begin(4,15); (4 = SDA 15 SCL)  i tested it with the Adafruit SSD1306 and the Acrobotics SSD1306 Librarys  both work.  Display size is 128x64 There are discussions on these boards on TＴＮ as a LORA node..or maybee single ch gateway? Heltec has a git :  https://github.com/Heltec-Aaron-Lee And there is another copy call TTGO https://de.aliexpress.com/item/TTGO-LORA32-868-915-Mhz-SX1276-ESP32-Oled-display-Bluetooth-WIFI
閱讀完整內容

micro SD card for ESP32, on lolin32 with OLED and heltec 32 lora oled

圖片
I have purchased 2 micro SD card holder for my esp project. First I would like to test with heltec esp32 lora oled module. this module uses: sck=05 MISO=19 MOSI=27 SS(lora)=18, then I assigned 21 for sd SS and there is a lib in esp32-arduino, which use SS default at 5 I took the example and use SD.begin(21), but I alway get the error: entry 0x40078a9c Card Mount Failed But I do saw once that it read out the sd card type and volume. Not sure it's the issue of lora sd card swithing, or it just can't work. The other esp32 card I have is an wemos esp32 oled, it did not leave me too much pins, I need to find out how to connect sd to it. But I have wemos D1 mini esp8266 on hand, and connect it as:  * The WeMos Micro SD Shield uses:  * D5, D6, D7, D8, 3V3 and G  *  * The shield uses SPI bus pins:  * D5 = CLK  * D6 = MISO  * D7 = MOSI  * D8 = CS It's not working with the example in the arduino IDE 1.8.5, which marked SD(esp8266), but it w
閱讀完整內容

Install Network Time Protocol(NTP) on BeagleBone with Angstrom linux and set local time zone

Referenced from : http://cwraig.id.au/?p=513 1. Update your Package List opkg update 2. Get the ntp Package opkg install ntp ntpdate Update 2014/07/03 for the latest beaglebone image(2013-06-20) with kernel 3.8.12, after this installation,  system will add to service list, so only need to change time zone 3. Now we need to stop the ntpd service so we can request a manual update /etc/init.d/ntpd stop manual update ntpdate pool.ntp.org type in date, you should see the date is changing to current date and time, but the time zone is not corrected. The time zone info is contained in /etc/localtime , use this to remove it: rm /etc/localtime before link up our time zone, look into /usr/share/zoneinfo folder for your timezone. I did not find taiwan in asia, not plan to use hong_kong, but there is still: /usr/share/zoneinfo/Etc/GMT-8 now we make the link with ln command ln -s /usr/share/zoneinfo/Etc/GMT-8 /etc/localtime now type date again to check, should ha
閱讀完整內容