Category Archives: CoCoWiFi

Sub-Etha Software announces more 2018 Chicago CoCoFEST! plans


Sub-Etha Software announces more 2018 Chicago CoCoFEST! plans

Des Moines, Iowa – March 14, 2018 – Iowa-based Sub-Etha Software reveals more plans for the upcoming 2018 27th Annual “Last” Chicago CoCoFEST! to be held April 21 and 22, 2018 at the Heron Point Convention Center in Lombard, Illinois.

“The biggest news,” says Sub-Etha co-founder Allen Huffman, “is that we will have Jolt Cola to drink during the road trip to Lombard, and maybe enough extra to share during the event.”

Among the new offerings at this year’s event will be CoCoWiFi, an inexpensive internet modem device that allows connecting the CoCo up to a WiFi network for accessing remote internet sites using telnet and other protocols. Both fully assembled and do-it-yourself kits are expected to be available, with pricing to be announced at the show.

CoCoWiFi is pretty cool,” says Huffman. “It looks like an old-school Hayes Smartmodem and can be used on any model Color Computer with any terminal program. If the MC-10 has a terminal program, I bet it would work there too. The best part about it is if you don’t wanna buy it, you can spend about $10 and put one together yourself without any soldering. But we’ll be glad to sell you one for much more than that.”

Another new offering will be SirSound, the serial port multi-voice sound device. SirSound provides (1980s) arcade-quality background music and sound effects from BASIC. It uses built-in commands with no assembly language or special drivers needed.

“SirSound is one of the funnest things I have ever worked on this month,” adds Huffman. “You can play the Frogger theme song just by typing a PRINT command. I expect it could also play the Pac-Man theme, too, but we haven’t tested that, yet.”

SirSound is still under development, as well as SirSound S (6-voices in stereo), SirSound Plus (SirSound with the ability to play stereo digital files) and Sir Sound S Plus. There will also be an open-source SirSound Jr project made available. It will have the most of the same features as SirSound, but will be limited to just 1-voice tone music. Beep beep.

“We also will have a selection of new-old-stock Sub-Etha items in original packaging for those who like to collect useless 5 1/4: floppy disks with photocopied instructions stored in plastic baggies. Of course, master disk images of all this stuff has been uploaded to the Color Computer Archive and will be available for free, too.”

Be sure to drop by Sub-Etha Software’s table in the main exhibitor hall during the event.

About Sub-Etha Software

Sub-Etha Software was founded in Lufkin, Texas in 1990, as a partnership between Allen C. Huffman and Terry S. Todd. It made it’s first CoCoFest appearance at the First Annual Atlanta CoCoFest in 1990, and it’s first Chicago CoCoFest appearance at the First Annual “Last” Chicago CoCoFEST! in 1992. They may be contacted online at

About the Chicago CoCoFEST!

The 27th Annual “Last” Chicago CoCoFEST! is sponsored by the Glenside Color Computer Club of Illinois. They may be contacted online at

Allen Huffman
PO Box 7634,
Des Moines, Iowa
Ph: 515-999-0227


How to load Zimodem firmware to an ESP8266 without Arduino IDE


  • 2018-02-25: Clarification on what ESP devices these instructions are currently limited to, per a comment from James J.
  • 2018-02-26: Added notes about versions for ESP-1, NodeMCU ESP8266-12E, and NodeMCU-32S modules.
  • 2018-02-27: Added link to Espressif tool for Windows that is supposed to do ESP32 modules (and also does ESP8266). If it works, I may update this just to use that one tool for both module types.
  • 2018-03-02: Removed second Windows option until I have confirmed how it works.

Updating ESP8266 / ESP32 Firmware

NOTE: These instructions are currently limited to devices like the NodeMCU ESP8266-12E and the NodeMCU-32S development kits:

An ESP8266 development board, available for under $9 from Amazon. (And much less from China!)

These devices have a built-in USB-to-Serial interface, so they can be plugged up to a Mac/PC over a USB cable for uploading firmware. However, the instructions probably will work with things like the ESP-1 module by using a USB programming device that interfaces it to USB.

ESP-1 module USB programming adapter.

Customized Zimodem firmware for all three of these platforms is now being created.

The excellent Zimodem firmware by Bo Zimmerman turns a low-cost ESP8266 module into a WiFi smart modem. One of the challenges users face is how to get this firmware installed on their module to begin with. I have been providing steps on how to install and configure the Arduino IDE so you can download the Zimodem source, build it, and load it.

But, if you aren’t a developer and don’t really want to go through that many hoops, you can take an existing firmware binary file and just load it directly.

Here are the steps as I know them, for Windows (with a nice GUI), or Mac OS X/Linux (command line).

Customized Zimodem Firmware images

I have a customized version of the Zimodem firmware on my server pre-built for the NodeMCU ESP8266-12E devkit, NodeMCU-32S devkit, and ESP-1 module. Download this firmware image here:

The versions will be named as follows:

  • zimodem.ino.generic-3.4.bin – for the ESP-1 module.
  • zimodem.ino.nodemcu-3.4.bin – for the NodeMCU ESP8266-12E development kit.
  • zimodem.ino.nodemcu-32s-3.4.bin – for the NodeMCU-32S development kit.

These names are the default names that the Arduino IDE creates, with the version number added.

Windows – ESP8266 NodeMCU Firmware Programmer

Download the NodeMCU flasher program. There is a 32-bit and 64-bit version:

NOTE: A different utility may be needed for ESP32. There is one that espressif (the ESP chip creator) provides that does both ESP8266 and ESP32. It is a .rar file, and when I downloaded it under Window 10, it ended up as a .man file (?). I had to rename that to .rar, and then find a RAR extractor (I used a free one from the Microsoft store). If you are using an ESP32, you may want to try this:


With your ESP8266 module plugged in (so it appears as a COM: port to Windows), open the NodeMCU flasher program and select that COM port:

On the Advanced tab, uncheck the default internal firmware (that is the option you would use to restore an ESP8266 module back to factory firmware), and browse to the new firmware in the second line. Checkbox that line, and set the start address to 0x0000.

ESP8266 Flasher for Windows – Config tab, for specifying the new firmware to load.

You might also go to the Advanced tab and increase the baud rate if you want the update to go faster. Once the binary file and COM port have been specified, return to the Operation tab and click Flash to begin the upload to the ESP8266.

ESP8266 Flasher for Windows – Operation tab, flashing in progress.

…and when complete…

ESP8266 Flasher for Windows – Operation tab, flashing complete.

You can now restart the ESP8266 module and it should be using the new firmware.

Windows – ESP8266/ESP32 Espressif Flash Download Tools V3.6.3

I have tested this tool on ESP8266, but not on ESP32 yet. I will update this section when I do. It requires more steps to install and setup, but may be what we have to use for ESP32. Running it offers four different parts it can flash:

Espressif Flash Download Tools V3.6.3 for ESP8266 and ESP32

I will update this tutorial when I have confirmed how to use this.

Mac and Linux – esptool

Install esptool (a Python script) and pySerial (a Python library for talking to the serial port):

easy_install esptool
easy_install pyserial

NOTE: I think I hadto run this as super user, “sudo easy_install esptool”.

Identify the serial port connected to the ESP module. This can be done from a shell (Linux) or the Terminal (Mac). On Mac, can look for devices that begin with “cu”:

alsmbpro:temp allenh$ ls /dev/cu*
/dev/cu.Bluetooth-Incoming-Port /dev/cu.HC-05A-DevB /dev/cu.SLAB_USBtoUART

If you do not know what to look for, you could do this command before plugging in the ESP8266, then again after you plug it in and see what appears. (On my system, I know I installed Silicon Labs drivers, so I recognized the “SLAB” name.)

On Linux, I think you need to do ls /dev/ttyS*. (I also saw an exemple using “setserial -g /dev/ttyS[0123]”).

Now that you know what serial port is connected to the ESP module,  run specifying that port, and the firmware image to use. On my system: -p /dev/cu.SLAB_USBtoUART --baud 460800 write_flash --flash_size=detect 0 zimodem.ino.nodemcu-3.4.bin

If it works, you should see something like this:

prompt$ -p /dev/cu.SLAB_USBtoUART --baud 460800 write_flash --flash_size=detect 0 zimodem.ino.nodemcu-3.4.bin v2.2.1
Detecting chip type... ESP8266
Chip is ESP8266EX
Uploading stub...
Running stub...
Stub running...
Changing baud rate to 460800
Configuring flash size...
Auto-detected Flash size: 4MB
Compressed 344528 bytes to 247587...
Wrote 344528 bytes (247587 compressed) at 0x00000000 in 5.8 seconds (effective 472.4 kbit/s)...
Hash of data verified.

Hard resetting...

You can now restart the ESP8266 module and it should be using the new firmware.

Over-the-Air Updates

Once you have this special build of the firmware, you will be able to do over-the-air updates. Make sure you configure your Zimodem for your WiFi network by going through the:


You can then use the command “AT&U” to see what the current version is. Bo is currently working on 3.4.

In stock Zimodem, firmware updates pull from Bo’s website for the two boards he support (the ESP-1, I think, and some flavor of ESP32). For my customized “CoCoWiFi” version, it will pull special builds from my website instead, and there are three different boards supported.

As I build new versions of this customized Zimodem firmware, I will place them on my server and you can type (from the Zimodem command mode):


That will get whatever version I have available. You should not need to do any more USB updates, unless something goes horribly wrong, or you want to go back to stock NodeMCU firmware.

Please let me know if this works for you.

CoCoWiFi and SirSound project updates

Things have been real busy lately at Sub-Etha Galactic Headquarters… Here are some updates:


The CoCoWiFi has been tested on the bitbanger serial port and things seem to work just fine.

On the RS-232 Pak, a modification was needed to make the pak actually receive data (forcing the carrier detect signal). This has been done by an easy soldering mod to the DB9 connector. The downside is that it does not provide true CD, and there is no support for hardware flow control or DTR to drop calls. For just a bit more, there are RS232-to-TTL adapters that provide hardware flow control, which might help for doing high speed transfers. However, the lack of carrier detect and DTR means they won’t work with a BBS like they should

Thanks to David Chesek, new RS232-to-TTL adapters were located that include all the signals. These would be the best choice for running with an RS-232 Pak. I have two different types of adapters, but have only done some initial testing. I was unsuccessful getting the first adapter to work. I plan to test the second version this week.

I hope to have a hardware announcement to make before the CoCoFEST!


I learned much while working on CoCoWiFi, so I returned to work on the previously “announced” SirSound project. I got everything wired up properly and was able to write a BASIC program to make it play tones. I also worked with John Strong and migrated the prototype over to an Arduino Nano (matching the original Arduino sound player board he sent me last year).

The next phases is to figure out the various modes that sound module will run in. I have proposed:

  1. Direct. This mode just passes bytes to the sound chip, the same way you might do with a POKE command if it was a memory-mapped chip. BASIC is very slow at ANDing and ORing bits to make the messages, which is how my test program works, but this could be heavily optimized. This mode is mostly here to allow someone to port over code that was written for one of the other platforms that use an on-board SN76489 sound chip, though some of the bit-blasting players would probably not work as well over slow serial.
  2. PLAY. This is the BASIC mode, that will simulate the PLAY command. You will be able to send a string of notes to SirSound and play them just as easy as in EXTENDED COLOR BASIC. There are a few things that have to be adapted, like support for the multiple channels of audio, and sub-strings. Last year, it was suggested to look at the MSX computer’s PLAY command for examples of how Microsoft did this very thing. I may follow that syntax. MSX also ads a PLAY() function that can tell is background audio is in progress, and we will be able to achieve the same results using the Printer Read/CD signal on the bitbanger port. I plan to also add some sequencing extensions so repeating music loops don’t have to be sent over and over again.
  3. Optimized. This mode would be for assembly programs, and would pack data into 8-bit values rather than longer ASCII strings.
  4. Interactive. I am planning on having a shell/command-line interface (CLI) available which could be accessed. It would be used for testing the device without needing to write a BASIC program.

More to come…