STE RTC DCF77

Current solutions and designs.
User avatar
DoG
Posts: 1125
Joined: Sat Apr 07, 2018 12:26 pm

Re: STE RTC DCF77

Post by DoG »

It get power from a adjustable buck converter and then fed through a MCP1700-3302E LDO to get 3.3V to the ESP-01S and the MAX3232 board. Connected to a MegaST.

SSID_small.jpg
SSID_small.jpg (20.81 KiB) Viewed 1307 times
Hardware3_small.jpg
Hardware3_small.jpg (247.49 KiB) Viewed 1307 times
DB25_small.jpg
DB25_small.jpg (52.61 KiB) Viewed 1307 times
czietz
Posts: 545
Joined: Sun Jan 14, 2018 1:02 pm

Re: STE RTC DCF77

Post by czietz »

Something is very weird with the communication. For example, when it says "Available Wifi networks:" and then, in the next line, "wifi", it is showing an echo of the command. But the device is not supposed to echo the commands.
czietz
Posts: 545
Joined: Sun Jan 14, 2018 1:02 pm

Re: STE RTC DCF77

Post by czietz »

Hence, you need to figure out what is causing the commands to echo in your setup. I suggest the following experiment:

Take a serial terminal program of your choice, configure it to 9600 bit/s, 8N1, no flow control. (And be sure to disable "local echo" by the terminal program so you don't get fooled.)

Then, with everything connected and powered, please press Ctrl+M, then type "vers" (without the quotes), then press Ctrl+M again. You should see an answer from the module like this:

IMG_5246.JPG
IMG_5246.JPG (30.33 KiB) Viewed 1291 times

More crucially, you should not see the command ("vers") being echoed (not even while typing it). However, your previous screenshot (from WIFICONF) shows that commands (like "wifi") are in fact echoed.

You can then start removing parts (e.g. unplugging the ESP-01) and see when the echo ceases.
User avatar
DoG
Posts: 1125
Joined: Sat Apr 07, 2018 12:26 pm

Re: STE RTC DCF77

Post by DoG »

As you said, still having echo, even after removing the ESP-01. So probably the Max3232 module. I don't have a schematics for the module and there is 6 capacitors on it which is a bit weird (maybe they have used 2 for bypass). It is so small so hard to measure.

Either desolder the Max3232 from the board and solder directly to the legs or order a DIP variant from a local seller.

Anyway, here is the output from AtariTerm:

20221106_150539.jpg
20221106_150539.jpg (201.86 KiB) Viewed 1257 times
czietz
Posts: 545
Joined: Sun Jan 14, 2018 1:02 pm

Re: STE RTC DCF77

Post by czietz »

The answer looks normal. Thus, the ESP8266 sees the commands and is able to reply to them. But it's the additional and unexpected echo that causes the client SW (be it WIFICONF or WIFISET) to choke.
User avatar
DoG
Posts: 1125
Joined: Sat Apr 07, 2018 12:26 pm

Re: STE RTC DCF77

Post by DoG »

Got the DIP version of MAX3232 from local store. Remade the PCB on veroboard. Fed it 3.3V directly. Now it is working great. I was thinking making a small PCB and fitting in a DB25 case. How fast is the ESP8266 on booting btw? Can you take 5V from the Atari and mount it inside instead?

SSID working small.jpg
SSID working small.jpg (26.64 KiB) Viewed 1202 times
New veroboard PCB.jpg
New veroboard PCB.jpg (83.27 KiB) Viewed 1202 times
czietz
Posts: 545
Joined: Sun Jan 14, 2018 1:02 pm

Re: STE RTC DCF77

Post by czietz »

DoG wrote: Wed Nov 09, 2022 9:24 pm How fast is the ESP8266 on booting btw? Can you take 5V from the Atari and mount it inside instead?
Never tried that. The module is ready to accept commands within 1 - 2 seconds. The connection to your Wifi will take longer; but there's a timeout in WIFISET to wait for that connection.
Post Reply

Return to “RTC (Real time clock)”