Legacy microcontrollers Forum Discussions

Hello,

I have a question about the efficiency of the Keil C compiler (V7.00e) when compiling for maximum speed of multiplication, division and addition operations. I need to ensure the compiled code for these mathematical operations is efficient and fast.

Does anyone know if there is documentation available which explains how to optimize the Keil compiler for fast multiply and divide operations? Are there any examples of how Keil compiles diffferent mathematical operations for the XC2000 and the correct syntax to use?

An example of the type of calculation required is given below:

(16bit result) = ((16bit input) * 123) / 4567

Can Keil take advantage of the MAC unit in the XC2000 core to perform the 16bit x 16bit multiplication above?


Thanks,
Chris Show Less

I'm using the XC888-8FF with my students for basic microcontroller training and small projects (thesis).

In the process of learning, students (and professors alike) write faulty programs.
One of my students, on testing such a program, activated FLASH protection.
I assume this is because he accidentally activated ROM code.

The problem is that once the FLASH is protected, there is now way to deactivate this, unless you know
the password. Since the protection was activated by a faulty program, we do not know wat this password is.

I would like to know:
-is there a general password that can be used to erase the device, and make it usable again?
-is there any option in FLOAD ore MEMTOOL, to deactivate the protection and erase the device, without password?

If this is not the case, the only option is to replace the device.

For the infineon reader: you have equipped the device with a watchdog to reboot when somthing (power glitch?)
disturbed normal program flow. This could also activate ROM code, and thus making the device unaccessible for
the user..... Show Less