I have the following code lines that worked well with SDCC compiler: data at 0x90 unsigned char motor1 = 0; // PORT 1 (90h) data at 0xB0 unsigned char motor2; // PORT 3 (B0h) But, when it does't compile with Keil. I'm trying to control a step motor by setting the values of these ports. How can I declare these variables in a way Keil compiles OK? Thank you.
"the following code lines that worked well with SDCC compiler ... it does't compile with Keil" Of course it doesn't - that's because it's SDCC-specifc syntax; not Keil syntax. If you want to compile with Keil, you must use Keil syntax! "How can I declare these variables in a way Keil compiles OK?" Read the Manual! Do the tutorials.