8051 Assembly to control switches

[Meero]

Hello,
I was wondering could you describe the code i need and the hardware configuration i need to control
input swtiches on a medical device. The switches are driven by 5 volts, could I just attach say P2 on my
AduC812 microcontroller to the switches. I need the code to activate every 10 mins. This is the algorithm:
Switch 1 pressed, delay (1 sec).Switch 2 pressed, delay (1 sec).Switch 4 pressed, delay (1sec). Switch 2 pressed
delay (1 sec). Switch 2 pressed again delay (1sec). Switch 2 pressed once more, delay 1 sec. Switch 3 pressed, delay 15 secs.
Finally, switch 1 pressed. 10 mins later start the process again.
A code example would be great.Thanks.

 

[IanP]

That depends on the current drawn by the switches. If it is less than, say 5mA, you can use 1k pull-ups and connect directly to the CPU pins. However, because it is a medical device you should use optical isolation (example:74OL6000 which is TTL-to-TTL buffer).
Code:

Do you know how to start, what pins would you like to select as DOs (digital outputs)...to activate Switches,.. are Switches activated by H or L level, what is the frequency of the CPU's clock (you will need this to setup timers to count time)..

;Definitions

Switch1 P1.0
Switch2 P1.1 and so on..

Next you will have to declare the following:

ORG 0000h
LJMP Start

ORG 000Bh
LJMP Timer0_Int ; Timer0 overflow..

ORG 001Bh
LJMP Timer1_Int ; Timer1 overflow..

Start: ; here the main code will start


Depending on which assembler you use the code will slightly differ..
Which 51 family member do you have?