Microcontroller basics - where to start - Page 1
Forum section: electronics / general

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: September 29, 2025, 02:33:54 pm
content: Hello,I am seeking advice on a path to learn more about microcontrollers.My goal would be to duplicate them.Specifically, I am interested in automotive microcontrollers from older vehicles (25 years old approximately)These microcontrollers are used on various control boards throughout the vehicle such as on HVAC control boards, Body Control Modules, Transmission control modules and the like.As the vehicles get older the chances of the microcontrollers failing becomes greater and I want to keep them running indefinitely.What tools would I need in order to read the data (if accessible?)I am also interested in learning assembly language or whatever is necessary to learn to create replacement microcontrollers from scratch if necessary.Obviously, this is a pretty tall order and I'm not even sure this is possible. Maybe like wanting to create atomic fusion, with no physics knowledge?Can you offer any suggestions? Below is a photo of one specific microcontroller I would like to duplicate. it is from a 2005 Dodge Grand Caravan.Than you

author: ejeffrey
author_rank: Super Contributor
timestamp: September 29, 2025, 03:16:08 pm
content: You can't practically "replicate" a microcontroller in any significant sense.The best you can usually do is to find a replacement. Automotive microcontroller have long life cycles and even if they are out of production you may be able to find old stock.The tricky part is programming them. You need to get the firmware. Most automotive micros will have security measures to prevent users from pulling the firmware. Often those security measures are broken but it takes a fair bit of research to learn how to bypass it for a specific part.I'm not sure it's true that microcontrollers often fail. Digital control modules are a know failure point but there are lots of ways they can fail besides the MCU itself giving out. The regulators, solenoid controllers, sensors, and IO drivers are all probably more exposed to the external world and more likely to fail. Also vibration and heat are as likely to affect the the PCB, mechanical assembly, or capacitors as much as the MCU. Replacing an MCU on a broken PCB may result in just frying the new MCU!

author: bingo600
author_rank: Super Contributor
timestamp: September 29, 2025, 03:16:14 pm
content: My guess would be Freescale (Old Motorola)https://en.wikipedia.org/wiki/Freescale_SemiconductorA lot of this automotive stuff is mask programmed and wo. any public info.Might not be an easy task

author: SteveThackery
author_rank: Super Contributor
timestamp: September 29, 2025, 04:20:29 pm
content: Basically I think you've got no real chance of replicating any of the ECUs you will find in a car. They are highly complex, often protected against reading or hacking, and you'll need to work out the CAN bus protocols used by the manufacturer to talk to it from the OBD2 port or similar.You can buy general purpose engine management ECUs such as the MicroSquirt and MegaSquirt, but they need you to program them with the engine maps. If there isn't a map available in the community you'll need a rolling road dynamometer and a lot of expertise.It might be easier to build a general purpose car ECU (perhaps you can buy them) and program it to operate the relevant part of the car without regard for the system-wide integration, but I can imagine error codes and lights on the dashboard.Honestly, I don't think it is realistic.

author: WattsThat
author_rank: Frequent Contributor
timestamp: September 29, 2025, 04:37:15 pm
content: As others have already pointed out… attempting to duplicate or recreate a ECU with a different microcontroller is not a realistic goal. The programs in the ECU’s are pretty well locked out of sight using various methods. Yes, given enough time and money, they could be reverse engineered but that’s not something you can do easily, I’d estimate about 10 plus years of experience and a $100,000 worth of equipment to get a controller to give up its secrets.The best you can achieve is to gain enough understanding of how microcontrollers work and how they interface to the external devices they control. This will aid greatly with troubleshooting and repair of existing ECU’s.Oh, a good starting point: a proper Arduino starter kit with modules. Something like this:https://www.amazon.com/Arduino-Starter-Kit-English-Official/dp/B009UKZV0A/ref=sr_1_1_sspa