Author Topic: Controlling Yihua 995D for USB control  (Read 995 times)

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Offline StealthrtTopic starter

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Controlling Yihua 995D for USB control
« on: April 12, 2021, 03:44:56 am »
Hi all. I recently purchased a YIHUA 995D SMD Rework Station and me being the geek that I am wanted to see if I could perhaps control it (via USB/ATMEGA) by using my PC and touch screen instead of physically doing so with my hands. Being able to control it via PC would allow me to mount the 995D under my desk and out of sight so that I have more room to work with on the top of my desk.

However, I have limited knowledge on "snooping" or "Reverse Engineering" and that is why I am posting my project ideas here in hopes that someone more knowledgeable will be able to let me know what all I need to do in order to accomplish my task.

I started out thinking I would just simply hook up the ATMEGA and just control the buttons/knobs and leave everything else as-is and just use a webcam focus only on the LCD to view what was on. Although that would work, its not ideal nor is it geeky enough  ;D .

The LCD screen seems to be controlled by the chip Holtek ht1621b. The website for it defines it as a "RAM Mapping 32x4 LCD Controller for I/O MCU". Here is the datasheet for it.

There also seems to be another chip which seems to be the main MCU? It's called the S3 Microcontrollers u820 s3f8s19xzz-qr89 and it's datasheet.

I've noticed that the IC above has a TX/RX UART line(s) looking at the diagram on page 9 of the datasheet.

Code: [Select]
9.7 Port 4

Port 4 is an 8-bit I/O port with individually configurable pins. Port 4 pins are accessed directly by writing or reading the port 4 data register, P4 at location F5H in set 1, bank 1. P4.0–P4.7 can serve as inputs (with or without pullups) and outputs (push pull or open-drain). P4.7–P4.0 can serve as segment pins for LCD or you can configure the alternative functions:

Low-byte pins (P4.0-P4.3): T0OUT, TBOUT, TACLK, TACAP, TAOUT

High-byte pins (P4.4-P4.7): TxD1, RxD1, TxD0, RxD0

Would this be something I could use to read and write the needed info/data to/from the micro controller chip? Would simply getting a USB to UART cable and hooking it up to those 2 pins work like it would when reading RS232 data on an Arduino?

I have high resolution images of the 995D here so that you can see the main board and all it has to offer for this to potentially happen.

So I am looking forward in learning from others on here as to what I could do for this to happen - or laugh at me and tell me its not possible at which will only get me more interested in doing it  :).

Disclaimer: Also posted on these sites:
« Last Edit: April 12, 2021, 03:33:29 pm by Stealthrt »

Online coromonadalix

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Re: Controlling Yihua 995D for USB control
« Reply #1 on: April 12, 2021, 02:19:48 pm »
if the yihua doesn't have an serial or usb port,  yes you'll have to reverse it in some ways

Maybe  replacing the control interface with say an arduino or any stm32 boards (arduino compatible) you could achieve something ...

Google search  and many projects are found, just add what you need ??


Offline StealthrtTopic starter

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Re: Controlling Yihua 995D for USB control
« Reply #2 on: April 12, 2021, 03:24:39 pm »

I've added a few more details to my OP.

Online coromonadalix

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Re: Controlling Yihua 995D for USB control
« Reply #3 on: April 13, 2021, 02:11:18 am »
I saw the specs,  but you see the rx or tx ports can be configured as i/o   the secret is in the code, and the config bits if there is ....  even connecting an usb to rs232 or any "usb to other interface" doesn't give any warranties that you can add an usb control .... if it's not designed for it, or to do it.

Since the s3f8s19 is a Zilog mcu, you need to check if there is a programmer who could read it ??

Development Tools
A complete line of development tools are available for Zilog’s S3 Microcontroller Family. The
development environment is composed of your application board, a target board, an emulator, and a host
PC running the IDE. Production programmers are also available from third party sources. Zilog’s in-circuit
emulator solution provides a wide range of capabilities and prices to suite most budgets and system
In-Circuit Emulators that support the S3 Family
 OpenICE-i500
 OpenICE-i2000
 SmartKit SK-1200
Target Boards for the S3F8S19 and S3F8S15 MCUs
 TB8S19, TB8S28 and TB8S39
 SPW-uni: single-device programmer
 GW-uni: 8-device gang programmer
 AS-pro
« Last Edit: April 13, 2021, 02:16:43 am by coromonadalix »

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