LED Signage with RS232 Port Operation Guide

The LED logo I found is a Pro-Lite PL-M2014R, consisting of 16 characters, each character measuring 5 pixels wide x 7 pixels high, for a total display area of ​​80 pixels wide x 7 pixels high (physical dimensions are 24 inches Width x 2 inches) High, Multicolor).

I picked this up from a local electronics recycling company for $10! They originally cost $40, but came with no accessories: no power supply, no remote control, no communication cable, no instruction manual. Operational status unknown, but I bought it for fun; supposedly it also has a Z80 microprocessor, which is also present in my Commodore 128 (I've never used it!)

Supplies

Pro-Lite PL-M2014R used LED sign

Minimum 2.5A 9V AC/DC power adapter with 5.5mm / 2.1mm barrel connector, center negative terminal

ESP-12 Wi-Fi module

4-pin RS232 breakout module

4-core RJ14 telephone cable

Step 1: First check if the flag is valid

The sticker on the back says this logo requires 30W of 9V AC (I've seen other photos that say 31W).

Power is Volts times Amps, so the amperage required is 30W ÷ 9V = 3.33A, or actually 3.5A.

However, even on the Pro-Lite webpage, they only offer a 2.5 A 9V AC adapter, which is the only power adapter that comes with these signs. 9V times 2.5A is a power capacity of 22.5W. I don't know why there is a discrepancy between what the power adapter can offer and the requirements mentioned on the sticker.

BUT: If you look at the labeled barrel jack connector, it's also molded "DC-IN". Can this logo be used on DC as well? Because I don't have an AC adapter.

So I set my 2.5A adjustable DC power supply to 9.06V (close enough) and plugged it in. The sign is on!

If the flag works, it's worth continuing.

Step 2: Build ESP-link interface

First, pay attention to the direction of the wires in the 4-conductor RJ14 phone cord. Mine are (from top): black; red; green; and yellow.

Anyway, it doesn't matter: the top and bottom are ground, and the middle two are RX and TX.

Referring to Figure 2, "Series II Wiring Assignments" from the Pro-Lite manual: Based on the fact that the locking handle is on the back of my phone's plug, I assume this means the black wire is the lower ground wire; red is RX; green is TX ;Yellow is the high ground. (You'd think that's what that means. I think these might be backwards, based on the actual connections I have that actually work. Anyway! If your connections don't work at first, try swapping RX and TX.)

Also note the difference between RJ12 and RJ14. The diagram in the manual mentions "RJ12", which is a 6-pin phone connector, but you'll clearly see the Pro-Lite logo using only the middle 4 pins. This is why the RJ14 cable works fine.

After that, we need to install Jeelabs ESP-link firmware on the ESP-12 module. I ended up using ESP-link version 3.0.14 because apparently, as of June 2021, the latest version has some kind of bug or instability. Pick it up here.

Instructions for flashing firmware are here.

Blink is not conceptually difficult, but there seems to be a lot of material to read through. The main complication is that you need to install Python, and then you need to install esptool.py. You may also need the Arduino IDE/flash utility, I only use it to find out which COM port is assigned to the ESP-12 module (mine is COM3).

The final command to flash firmware is of this form:

python "../esptool/esptool.py" --port COM3 --baud 115200 write_flash --flash_freq 80m --flash_mode qio --flash_size 32m 0x0000 boot_v1.6.bin 0x1000 user1.bin 0x3FC000 esp_init_data_default.bin 0x3FE000 blank.bin

(But the exact details depend on the folder where you have python, where you put esptool.py and the esp-link firmware, and the COM port assigned to your ESP-12 module.)

Once you have ESP-link running on the module, you need to log into it with your phone (it will first run in "AP" or "Access Point" mode). You have to browse to the wi-fi router and you will find that its SSID is "ESP-xxxxxxxx" (something like this, ESP plus its Mac address). You don't need any Wi-Fi password or any security measures to connect. Then use a browser to access the ESP-link configuration page:

http://192.168.4.1/

Use the web interface to configure the module to log into your own Wi-Fi router, so you must have your Wi-Fi router password ready for this. Then restart the ESP module and find out the IP address it obtained via DHCP, then log in again via your own Wi-Fi network.

The first thing I did was assign a static IP address to the ESP-12 module, restart it again, and then direct my browser to that static IP address.

at last. . .. . .In the "Home" menu (selected from the left side of the browser page) you will select the pin assignment preset "esp-12 swap".

This preset will contain the following specific settings:

Reset (gpio1/TX0)

ISP/Flash (gpio3/RX0)

Connect LED (gpio0)

Serial LED (gpio2/TX1)

UART pins (swap)

RX pull-up (checked)

Step 3: Add RS232 breakout module

The ESP-12 module does communicate via UART, but this is done at "TTL" voltage levels.

TTL voltage levels are not sufficient to communicate with RS232 devices such as LED signs.

That's why the RS232 breakout board is there: it's used to amplify the signal so that the sign can recognize the message.

The connection is very simple, here I have done it using a breadboard.

The RS232 breakout module uses 4-pin connections: VCC; TX; RX; and GND.

All you need to do is jumper (from ESP-12 module to RS232 breakout module):

3.3V to VCC

ground to ground

GPIO15 to RX

GPIO13 to TX

Now as for the phone line connections, there are only 3 connections:

Yellow or black, connect to DB9 pin #5 (ground)

Green wire (flag TX), connect to DB9 pin #3 (TXD)

Red wire (symbol RX), connected to DB9 pin #2 (RXD)

Forgive my poor welding job! I don't have the male DB9 connector yet, it's on its way in the mail. At the same time this is enough to confirm the communication.

Step 4: Connection Configuration

Therefore, using your web browser, log back into the ESP-12 module and select "μC Console" on the left side of the web page. For communication, you need to set the baud to 9600 and the "Fmt" format to 8N1. Make sure to add CR and LF (lower right corner of the console window).

Then press Enter a few times on the Console Entry line and issue the command ""ID01"" to the signature.

If all goes well, you will get the answer ""ID01"S".

You have to do any necessary troubleshooting on all previous work until you get an answer from the flag, because until then you still have no communication with the flag.

This "μC Console" is enough to program the flags, but there are a few next steps you might want to consider.

One is PuTTY for Windows and the other is com0com (which assigns a virtual COM port to the flag). (Note: I have no idea how "com0com" actually works, I'm just mentioning it for completeness. I've read elsewhere that you would use it to create a virtual com port that you can then combine with your Use it with your own custom program if you want to go that far).

I just downloaded 64-bit PuTTY for Windows and ran it, then set up a telnet connection (port 23) to the static IP address I assigned to the ESP-12 module.

Telnet is essentially a terminal emulation and you can't really tell what command was issued and what response was received, but here I will explain what communication is happening on the black screen.

First I sent an Enter (blank line) to the flag and then ""ID01"". The flag responds with "<ID01>>S", which is its standard response. ""ID01"" is the identification code of the mark, and the code "S" means "sent successfully". Other possibilities are 'E' (error) or 'F' (buffer full).

Finally, I sent this command to the signature:

"ID01" "PA" "FQ" "SD" "CB" C "CE" O "CL" L "CD" O "CG" R

"ID01" "PA" - This tells the flag with identification code "01" to wake up and reprogram page "A" with the following:

"FQ" - "Appear" (no animation effect)

"SD" - "Bold Italic" (bold means 2x width)

"CB"C - "Red" and the letter "C"

"CE" O - "bright orange" and the letter "O"

"CL"L - "bright green" and the letter "L"

"CD" O - "orange" and the letter "O"

"CG" R - "yellow" and the letter "R"

Finally, there are programming resources for various signs posted on the Internet. Frankly, I find them universally disappointing: don't waste your time. Instead, here's a simple protocol released by Pro-Lite itself, depending on your ROM version. You may have seen that on the foil sticker on the back of my sign is the V6 sticker, indicating version 6 roms. You may have an earlier V5 rom or a later V8 rom. Whichever you own, here is a copy of the Pro-Lite Protocol Guide. Just follow the protocol documents published by Pro-Lite itself, and do not pay attention to the opinions and misinformation posted by others on the Internet.