ESP8266 Community Forum

- Thu Apr 23, 2020 1:22 pm #86726 Thanks for the comments Mike!

1. If someone could point out any information that would explain why I can read data just fine using Serial - USB converter by connecting data and ground cables from Helix 7 that would be great! Is serial - USB converter actually doing something about the signal that ESP8266 can’t do? With Tera Terminal I was able to read data just fine so I’d assume Helix 7 is sending readable signal. I guess I just don’t yet understand this topic enough to even ask the right questions. And since on one of the first posts on this thread I posted a link to R Heslip’s work and there was nothing about having special hardware, I’m having hard time adding extra hardware until I understand what should be added.

BTW any recommendations for a affordable scope?

2. About UART’s...I did some research and it looks as if the are 2 UART’s available for serial communication. UART0 (RX&TX Pins). UART0 pins can be swapped (to UART2) but it would still use the same UART0, just using it via different pins (13&15). UART0 is also being used with the USB. And then there is UART1 that can only send.

So if UART0 is busy listening USB and UART1 can’t be used for receiving and changing UART0 to pins 13&15 would still be the same UART0. How can we use serial monitor via USB to print information being received via UART0?

https://tttapa.github.io/ESP8266/Chap04%20-%20Microcontroller.html


Communication

Serial

The ESP8266 has two hardware UARTS (Serial ports):
UART0 on pins 1 and 3 (TX0 and RX0 resp.), and UART1 on pins 2 and 8 (TX1 and RX1 resp.), however, GPIO8 is used to connect the flash chip. This means that UART1 can only transmit data.

UART0 also has hardware flow control on pins 15 and 13 (RTS0 and CTS0 resp.). These two pins can also be used as alternative TX0 and RX0 pins.

- Thu Apr 23, 2020 7:14 pm #86730 I have off and on been trying to accomplish this for about 2-3 months. I have been using jcables' nmea-link build you can find it at https://github.com/jcable/nmea-link I have been able to get it uploaded and working with the simulator as i am able to see the data and connection in navionics, i can also see the nmea data in arduino. The problem im having now is when trying to connect to navionics its not detecting or seeing my unit anymore. with the way its behaving i feel like its a simple setting issue somewhere quite possibly by fault of my own. I was trying to use a rs485 to ttl converter but im not sure it will work or not as im by no means a programmer and have no idea if it would work with the coding that is there. From reading around alot of people who have had this type of system working, they used bidrectional logic level converters between the esp8266 and sonar unit. I have ordered some and will be seeing if thats the issue when they arrive.

This is another project that looked promising to me, maybe you can find something useful between the two
https://kb7kmo.blogspot.com/2015/09/nme ... ridge.html

If you find anything out let me know! those live contour maps are going to be EVERYTHING on the water.

- Fri Apr 24, 2020 8:16 am #86739 Jonathan,

Would you mind sharing the code that you used to get NMEA data to show up on your arduino? Would like to understand how you achieved this.

- Fri Apr 24, 2020 2:38 pm #86745

BTW any recommendations for a affordable scope?

There are many USB or USB+WiFi scopes for ~100 USD. I personally use the Hantek 6022BE. In My opinion these inexpensive scopes work well for signal frequencies < 1MHz. Here is a link to some recommendations:
https://www.electronicproducts.com/Test_and_Measurement/Benchtop_Rack_Mountable/Top_7_USB_oscilloscopes_for_makers_and_pros.aspx#

Some comments about RS-232 voltage levels. I believe that Humminbird calls their output "RS-232" per https://www.humminbird.com/sites/humminbird_site/files/ais_connection_ig_532458-2_a.pdf

I found this to be a good summary of the RS-232 at https://www.sjoerdlangkemper.nl/2019/03/20/usb-to-serial-uart/:

Voltage levels
UARTs use two voltages: one voltage indicates a 0 bit and another voltage indicates a 1 bit. What voltage exactly is used depends on the device:

RS232 serial ports use negative and positive voltages, up to -15V and 15V.
Some devices use 0V and 5V, such as an Arduino Uno that runs on 5V.
Most devices use 0V and 3.3V.
Some devices use 0V and 1.8V.
For RS232, negative voltage is a logical 1, positive voltage a 0. For most other UART devices, 0V indicates a 0 bit and the higher voltage indicates a 1 bit.

To avoid frying your device, it is important to use the correct voltage. Connecting your 3.3V bridge to a 15V RS232 line will quickly destroy it.

Voltage that ranges between 0 and power supply voltage (Vcc) is also called TTL voltage levels. 5V TTL voltage levels consider everything above 2V a logic high, and can thus also receive data from 3.3V UART devices. So in that case it is possible to communicate with a 5V UART using a 3.3V UART.

It could be that you only need to invert the Helix 7 Output before connecting to the ESP-12E.
Mike