Frank,

Interrupts make this much easier.

Upon timer interrupt check switches.

Upon Serial interrupt input serial data.


Each interrupt can set a condition flag (i.e. message terminator rx'd = msg in) and (switch change = on/off).

Now your foreground just needs to poll the state of these flags.

jnb switch_change_flag,do_switch
jnb msg_in_flag,do_message.

If you have a simulator you'll get interrupts happening quickly.

regards,
p