Atmel C51, User Manual

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Operation Mode
C51 Microcontrollers Demo Board User Guide 3-14
4119C–8051–3/03
After the download of the HEX file, the program asks if you want to download another
HEX file in the second zone of the external Flash memory.
In this case you’ll have to switch MAP SELECT (to access second zone) and send
another HEX file in text mode.
All the external flash memory (128K bytes) is erased when ISP is used, even if you only
want to download one zone.
If you have one external Flash memory zone programmed, and later you want to add
another program to the second memory zone, you will have to download both programs
at the same time.
Note:
The data transfer is seen on bar graph.
3.3 Demo Mode
In demo mode, programs stored into external flash memory are executed to demon-
strate capability of Atmel Microcontrollers. To run external code we must have EA=0.
In this mode the first four bits of J11 (UC3:0) are used to select demo program and UC4
is used to select display (LCD or RS232).
Figure 3-7. Switch Utilities in Demo Mode
3.3.1 C51 Mode In C51 mode (Non Page Mode) switch J8 must be as shown in Figure 3-8.
J11
PSEN
ALE
ISP1
Use
r Co
d
e
1
0
1 0
J11
J9
J16
J9
J16
EA
MAP SELECT
ISP2
Used to select demo program
Used to select display
Used to select memory zone