Chapter 9. FAQ
If you are a learner, here are those frequently asked question for your reference. When you have problems, read those questions first and carefully. They are very useful to you.
1. Why doesn’t the K5MDP work, after successful MCU programming?
Firstly, check the MCU to see if AT89S51 is correctly installed in the socket. SST89E516RD is not applicable for programming.
Then, check to see if the system is properly reset. If not, press the reset key.
2. Why the system is not online for emulation?
SST89E516RD must be correctly install in the 40-pin socket to emulate. Monitoring program must be burned inside the SST89E516RD.
The Keil uVision 3 must be installed at C:\, root directory. Installed in other directory may cause trouble to emulate with Keil. It’s strongly suggested to save source file and project file at the same directory.
3. Emulation on development board is ok, but emulating target system doesn’t work, why?
Check the development board’s reset circuit, crystal unit, and check to see if programming works.
Check the direction of the emulator head. Note that the 1st pin of the emulator should connect to MCU’s 1st pin.
4. Why does some program run correctly after programming, but not at emulation?
Emulation uses some of the MCU’s resource, that is, not of all hardware resource can be emulated. Programming the MCU and then running is the best way to check your program.
5. How can I use 89C2051?
Compared with 89S51, 89C2051 lacks of P0 and P2 port. Except for this, there’s no difference between 89S51 and 89C2051. It’s completely correct to use 89S51 instead of 89C2051 in experiment, as long as P0 and P2 port are not used in your codes.
If using 89C2051 is a must, we suggest you to use other programmer we offer.
6. Is 89S51 the same as 89C51?
89S51 is the update of 89C51. They have the same instruction set. 89S51 is cheaper and has longer life than 89C51, and 89S51 is enhanced with watchdog timer and ISP features.
7. The HEX file of example programs in accessory CD doesn’t work correctly after programming into AT89S5x, what is wrong?
Check the 4-bit toggle switcher to see if switcher is correctly toggled.