Hardware update--basic functions tested

A project log for Fairchild F8 38P70 Development Platform

Creating a Development Platform for the Mostek 38P70 version of Fairchild's quirky little F8

craigCraig 05/10/2022 at 17:520 Comments

Board testing

Boards are back from the fab house and i have partially populated to do some initial tests.  So far, everything is checking out OK.  I have tested the external interrupt, have been able to write to the displays, read/write the serial port, read/write to the RTC, read/write to the digital I/O (switches, LED, speaker).

Display dimming

Has anyone successfully dimmed the 2416 display across any meaningful range? While waiting for the boards, using a function generator i tested PWM dimming on some of my DL2416s and found that none of my Litronix versions of the display appreciate the dimming signal.  I could not find a frequency that would uniformly dim the display and most frequency ranges really messed with the internal refresh clock.  So I do not plan on even populating the dimming circuit unless i can get my hands on some other manufacturers' 2416.  The dimming may work with the newer 5x7 matrix display but i have not tried.


i am using the DASM assembler which, despite it's limitations, has provided functional code for board testing.  If anyone knows of a more capable assembler for the F8, please let me know.