On Mon, Dec 15, 2003 at 11:21:10AM -0800, Vintage Computer Festival wrote:
On Mon, 15 Dec 2003, Dwight K. Elvey wrote:
Does anyone have a data sheet for a Motorola
MC6825?
I believe it is a USART but I can't find anything on
it. It is from the late 70's.
I can only imagine at this point that it was a custom or internal part
because I can't find any mention in any of my Motorola data books
(several) nor the Master Selection Guide (1992).
Do you mean by chance the MC68HC25?
This is an I/O expander (port replacement) chip for various microcontrollers
such as the 146805E2, 6801, 6801U4, 6803, 6803U4 and 68HC11.
It comes in a 52 pin PLCC package.
Its purpose is to provide the I/O ports of a microcontroller that get "lost"
if the system is expanded with external ROM/RAM (some ports of these uCs then
are used as the data bus and the multiplexed address bus).
The data sheet I have is from 1990, not 1970's, though.
Holger