Serial I/O with a Motorola MC68HC11E1 MCU

Posted on 1998-05-20
Last Modified: 2008-02-01
I've got a Motorola MC68HC11E1 microcontroler with a small program on it. What I need to do is write a GUI interface to upload config data to certain memory locations and download stored data from other memory locations. I can do serial I/O in MFC but I need to know how to read/write to memory locations on the Microcontroler through the Serial Communications Interface. Even more basically will the MCU do this or do the upload/download routines need to be written into the onboard program?

Answers, references, suggestions, and/or comments appreciated.
Question by:beyondrob
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
LVL 32

Accepted Solution

jhance earned 150 total points
ID: 1135484
The 68HC11 has a programmable UART (i.e. serial port interface) implemented in it's hardware.  In order to do what you want, however, you must write a program that runs on the 68HC11 that will watch for and accept commands from your Windows program to read/write memory locations and do whatever other tasks you want it to.  Rather than spend a lot of time writing a custom Windows application to do this, why not just use Hyperterminal (which is included with Windows)?  

Author Comment

ID: 1135485
We've got a program (PCBUG11) that interfaces with the microcontroler already. From the documentation it uses motorola's S-records. We are planning on doing it this way right now and emulating the basic program that came with the documentation to upload the data. Do you see any problem with approach?

I'm doing the Windows program since the config will be being used by not technical people who need a simple UI to work with.
LVL 32

Expert Comment

ID: 1135486
I understand now why you want to write a Windows GUI.  Using PCBUG11 (or a modification of it) should be straightforward.
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!


Author Comment

ID: 1135487
The problem is is that I don't (didn't) have an Idea of how PCBUG11 did what it did. I'm hoping the S-Records are the key. I'm going to give you the points I just wanted to get in some comments while I could to make sure I wasn't going about it all wrong.
LVL 32

Expert Comment

ID: 1135488
There is nothing magic about Motorola S record format.  It's been around since the original MC6800 development kit.  It is supported by almost all embedded processor compiler/linkers and also my almost all EPROM programmers.  If you need details on the format, I'm sure I can dig something up for you.  Im sure that the PCBUG11 program is just a simple debug monitor program that is designed to help debug a 68HC11 embedded system.  Since these systems don't typically have any kind of UI or console, a tool like PCBUG can help you out a lot.  It just watches for commands on a serial line and does what you tell it to do.  Usually you can do things like examine memory, set locations, toggle IO ports, set breakpoints, and start a program executing.

I haven't used PCBUG11 myself, but I have used many other similar tools.  Even wrote one for the 6502 when I worked for Rockwell Intl. back in the 1980's.

Author Comment

ID: 1135489
If you've got any info on S-Records, the MCU, or how PCBUG controls the MCU over the serial port it'd be much appreciated. I need to know what the commands over the serial line are so I can make my program do them.

Expert Comment

ID: 1135490
ok I have the same kit
we first faced the problem of uploading your assembly program via kermit from win95
the solusion was to reboot and start this from dos

as a result I was not encouraged to make any interface for the kit on win95


Featured Post

Salesforce Made Easy to Use

On-screen guidance at the moment of need enables you & your employees to focus on the core, you can now boost your adoption rates swiftly and simply with one easy tool.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In this article you will get to know about pros and cons of storage drives HDD, SSD and SSHD.
Arrow Electronics was searching for a KVM  (Keyboard/Video/Mouse) switch that could display on one single monitor the current status of all units being tested on the rack.
Are you ready to implement Active Directory best practices without reading 300+ pages? You're in luck. In this webinar hosted by Skyport Systems, you gain insight into Microsoft's latest comprehensive guide, with tips on the best and easiest way…
Finding and deleting duplicate (picture) files can be a time consuming task. My wife and I, our three kids and their families all share one dilemma: Managing our pictures. Between desktops, laptops, phones, tablets, and cameras; over the last decade…

737 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question