New project : ComeNCapture

ComeNCapture is a small project, Quick and Dirty logic analyzer based on STM8L mcu. I wrote a little code for this project. Using timer 4 interrupt for adjustable data sampling rate. By manipulating 2 variables, ARR and prescaler. By using USART and baud rate of 115200. With USART interrupt, I can control when to start ot stop the data sampling. By sending 3 bytes {Start/Stop, ARR, Prescaler}. The start and stop is 0x01 and 0x00. ARR and Prescaler are the important for timer interrupt. I will get into this later.

For example. I want to capture the 50Hz square wave to see the duty cycle. I need the sample rate of 100Hz. A.K.A 2x ; x is the target frequency that we want to capture.

But the big problem is I’m not sure that it will work. And if yes from my perspective, It’s 0% reliable.

Link to project is Here

Six years of finding the datasheet and pinout of the MN15439A

Chapter 1 : Beginning

6 years ago. I got the old CD car player made by SONY. It’s CDX-GT700D and this CD car play having such a fascinating feature. That is the Graphical Display with the the Blue-ish like 488nm laser ! So I don’t delay de-solder-ed that day. removing the display and thrown the rest panel board, leaving only bare Display. It’s turned out to be Vacuum Fluorescent Display  or VFD .

Here’s the demo :

Chapter 2 : Hunting Haunted

Year later, I just finding old stuffs that I have and found this Display, I took it from the box and start looking at the back of the display. Then I noticed the the weird shiny brand “Noritake itron JAPAN” and marking MN15439A on the opposite side (We’re still on the back).

then I googled this up but found nothing, I start by going to the Noritake Itron ‘s Website in the VFD section also found nothing, but at that time (Grade 8) my English skill isn’t great likes today, So I gave up on that. Then I contacted to one of employee by the contact email on their website. They said

Dear classified name / Thailand
The P/N : MN15439A is designed for particular customer.
Unfortunately we can not open any of the information
about this exclusive customer.
Thank you for your understanding.

OK. Not what I expected though …

Another year passed still no clue what the heck is this stuff, I went to their website again to grab the similar display’s datasheet and compare with this SUCKER (oops, little explicit xD). and I draw the pinout of the MN15439A (At then, I guess that it’s right, and absolutely YES!) not exactly remember what display is used as reference (possibly MN14440A or MN14416A). back then my hand writing still sucks as right now lol.

Chapter 3 : Electrically thinking

Everyday I went to school, And I known one teacher (who used to be an adviser of friend’s school project) He is the top form in Electronics, He design his own switching power supply, making his own Sumo robot and a lots more of electronics things (including Microprocessor/controller this from ASSEMBLY to BASIC and C/C++). I ask him for some help for how to correctly drive the Display’s filament heater (electron shooter) and he said that it both works with DC and AC at about 3.3 volt (which is right).  Big thanks to him. but unfortunately He passed away 2 years ago (2018) due to cancer. but his wife told me that he’s very smart guy but since he was teacher. He works hard and some day he doesn’t event come back home, his wife said. Anyway don’t be sad -> Lets dig deeper

Today, I decided to write this blog (2020/5/1) because something just hit my brain and telling me to pick this old display up along with my GU280x16G-7000 from project  FakeGrayscale. I start to search again after 6 years. Now I have the better English language that 6 years ago (I believe xD).  I went to [Noritake Itron] website again to download ALL of datasheet that available for downloading. Finally found two that having exactly same pin number are the MN14440A and MN14416A. . But I’m skeptical that the custom made likely having entirely different pinout. new Idea just pooped up in my head. I quickly go to google my activities site and use keyword CDX (that What I remember) and the “CDX-GT700D” trigger my memory. quickly search for service manual.

Chapter 4 : Reveal the truth

Good luck, I found the service manual online and download them, surprisingly found the PCBs and Schematics. And boom !!! the Display PCBs

The first page of service manual :

service_manual

PCB layout :

service_manual2

YEAHHHHHH. Finally. after 6 years of finding. It’s here ! The MN15439A

service_manual3

Comparing with the actual thing :

Great match, After that I took some look at my drawing from many years ago and I was right back then.

Chapter 5 : What’s next ?

*at this point. I forgot to tell you that the MN15439A uses the Chip In Glass – CIG Technology by putting few shift register on the glass inside display. Each shift register has hundreds of bits (up to 288 bit !)*

reaching this part. I’ve mad a plan to design the 50-ish VoltDC boost converter for the VFD and do some code with STM8L (seriously ?!?!?). I will include the links to the display I used as the pinout reference (which is match) and some more details of that display.

All the data I used is here.

MN14440A – brief datasheetMN14440A full datasheetCDX-GT700D service manual

LTL-7100M-HB : The super weird bi-color LED bar graph.

Month ago, I got some very rare LED bar graph from yoycart ( Chinese taobao agent) here.

And this is some bit from datasheet with the Charlieplex-like connection of bi-color LED (green,Yellow)

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Now we have the diagram, It’s time for the real thing up and running ! As again. No arduino this time, just bare metal STM8L151F3U6. My choice beside Arduino for quick prototyping.

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Looks like Photoshop-ed uh? Now some closer look. Compare to my stm8l dev board.

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Lovely TINY. Barely sit on the bread board

 

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Back-lit TI-82 is done !

Hi guys, I’ve been working for several days, And now it working !

Originally, I plan to use (and should use) the 560uH inductor. but due to COVID-19 outbreak. It cause most of economy shipping companies to slow the process down. All of the parts arrived fine except the inductor (which is suppose to arrive first but not).

u0e98c7019a944badb2a6174c030a934ev

So I need to find the inductor that not less than 560uH, and luckily found one. the 1mH. Technically should be store energy mush more than the 560uH, but it uses for voltage boosting, So it works fine.

Then I build up the things, soldering everything together on the PCB. ( Also I got fake HV823 !).

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And Everything works fine ! Here I connected to the DC-DC booster from 5 volt to 9 volt and it very bright !!!!

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after gone through many process (both off and on camera). Everything seems fine until now 😀 (Note that ripple effect caused by camera, In person is flicker-free).

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some Reflection reveal the tape I used to stick the EL panel with LCD together, as well as the soldering spot on the EL panel.

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After reach this part, It mean that this time I’m typing, the project is done and still in process of video making.

COVID-19 affected all of my project

Hello guys. After couple months of covid-19 lockdown, pandemic, etc… My projects had been delayed and no where to be finished. Including

  1. FlexWatch 0.1
  2. ELmod82
  3. <CPU load monitoring via i2c bus on PC monitor for pc running linux, haven’t got the name yet 😅>

But at lease, I have enough time to made some video series for the stm8l for noob (not really for noob lol). Anyway stay tune on my YT channel.

STM8L template updates!

I’ve made some update to the stm8L template, The updates including

  • USART is working ! with the example code !!!
  • Also made the configurable USART speed in usart_init();
  • I added my new little library call “dev_id” for reading Device Unique ID (according to datasheet), as well as example code
  • I also ported the TIM4 delay and made example (the delay with TIM4 originally coded by Shawon Shahryiar on embedded-lab.com). This delay will soon replace original delay. This one way more precise (soon will make one compatible with external clock source)
  • added LEDring code, soon will replace the AVRingLED project.
  • changed the CPU speed to 16MHz at default

I will made more update (Incuding Hardware SPI , I2C, BEEP and some IrDA (SIR) Things! So please calm down and wait me done my stuff. I won’t make you disappointed 😀

Link goes here 

TI-82 calculator !

Yesterday (2020/2/2) I received my Graphing calculator from Denmark , but that is not t he point. It’s TI-82 calculator. The USER-FRIENDLIER TI-85. Although, the online world in 2020 still lack of the useful Information and modification, But I found on the ticalc and someone made the TI-link compatible cable (Black link compatible) and someone had jammed the EL backlight for illuminating the screen !, So in think 2 months of vacation, I would like to make it better by adding EL backlight and made my own TI-link the linking cable ! and here is a bit of some photos I took.

So I will put some link down below for the PCBs order link from OSHpark. (Will include github repo as well on that link)

SerialLink (My TI-link clone)

ELmodPCB

Project Aut0rien almost done !

After few days I came across the idea about to put the accelerometer sensor (ADXL335) into the laptop for detection the rotation of the screen using the Earth gravitation acceleration. reading the x and y axis from the ADC (ADS1115) connected to the I2C port (VGA — i2c-1) using the compiled binary from C to run on the pc at the boot. but I’ve been waiting for the sensor module to arrive. maybe soon I will make some video on Youtube.