Hi,
I am using Intel 386EXTC parallel port1 and have connected 8 LEDS on P1.0-P1.7. Below is a small assembly program that I write in 512K Flash that uses UCS as chip enable. LEDs need a high on P1.0-P1.7 to light hence P1LTC is configured as ffh. when I power on my board, LEDs should light up but they don't. I don't understand why? Is it something to do with M/IO# signal. Should there be a decoding logic where Flash CE is created from M/IO and D/C# signals? CS1 from processor is tied to SRAM.
Is it possible that I need to reconfigure address registers REMAPCFG for expanded I/O space?
.model tiny .386 .code
main PROC jmp Start
P1CFG sword 0F820h P1DIR sword 0F864h P1LTC sword 0F862h
Start:
mov ax, 00h mov dx, P1CFG out dx, al
mov ax, 00h mov dx, P1DIR out dx, al
mov ax, 0ffh mov dx, P1LTC out dx, al
org 0fff0h jmp Start
main ENDP
END main
Any suggestions are appreciated
thanks learner