68hc11 f8   (SOLVED  Its an A8) - Page 1
Forum section: electronics / general

author: mr ed
author_rank: Regular Contributor
timestamp: January 29, 2024, 09:50:36 pm
content: I'm trying to find details on the f8 version of the mc68hc11f8 and i am finding nothing. It exists as spare parts are available on eBay and was used in tektronix products. I am most interested in it's special boot mode lots on a8, FL etc. Was it orphaned? From about 1990.

author: Benta
author_rank: Super Contributor
timestamp: January 29, 2024, 10:06:57 pm
content: Nver heard of it. And I worked together with Motorola for 30 years.

author: coppice
author_rank: Super Contributor
timestamp: January 29, 2024, 10:11:45 pm
content: Its 30 years since I touched an HC11, and I can't remember too much about them. The suffixes which define the actual parts within the family seemed to be allocated fairly randomly, and I have no idea what the F8 variant might be. However, is this the boot mode you are referring to?http://www.orgler.it/sw-boot.htm

author: mr ed
author_rank: Regular Contributor
timestamp: January 29, 2024, 10:45:13 pm
content: OK, misread fuzzy schematic, it's an A8.

author: mr ed
author_rank: Regular Contributor
timestamp: January 30, 2024, 12:02:57 am
content: Trying to understand a tektronix product firmware update.It normally runs code in external flash 64k in 2 chips.Updating requires modB held low and reset. Some code(not buffalo I think) runs , somehow to erase eeprom, ext flash, maybe config reg.Then s19 buffalo is loaded (why not the rom buffalo I don't know) and the app code gets loaded into ext flashI will look carefully at the details now that I can get bit accurate a8 description.

author: Andy Chee
author_rank: Super Contributor
timestamp: January 30, 2024, 03:35:30 am
content: When I was playing with HC11 many moons ago I used BUFFALO. However the other technique is to use PCBUG.You can use PCBUG on a modern computer through DOSBox (on a Windows, Linux or MacOS machine). DOSBox will need to be configured for a serial port, using a modern USB-serial device. The PCBUG instruction manual contains the basic HC11 wiring hookup.Incidentally, if you have confirmed that your device is an A8 variant, then that is the masked ROM version. You might not be able to read out the internal ROM if it has been code protected, though I suspect in the many years since its manufacture, there have been techniques developed for defeating the code protect (which I don't know).Of course, if you purchase an A8 variant from eBay, be aware that it won't be blank ROM, it will be a masked ROM from some unknown application (or a fake/remarked chip).If you want to attempt to program a new device, the new device should be either a 68HC711E9 OTPROM (make sure it's blank though! or find a windowed EPROM version) or 68HC811E2 EEPROM variant. It will require minor changes to the source code for microprocessor configuration from your existing A8, once you dump the A8 ROM.Actually you mentioned that your A8 in your tektronix uses 2x 2764 EPROMs? If so it's possible that your A8 is configured for external memory, in which case the internal ROM is bypassed and not used. If external memory is confirmed then a random A8 from eBay may work, as well as A1, E9 & E1. If the tektronix doesn't use internal EEPROM either, then A0 & E0 may also work.Good luck!