1. 8051 Development System Details
EE/CS-352: Embedded Microcontroller Systems

2. EE/CS-352: Embedded Microcontroller Systems
Program Download
Program gets downloaded via a JTAG protocol to flash memory in the chip.
EE/CS-352: Embedded Microcontroller Systems

3. Assembly / Compilation
Assemble/Compile – only assembles, used for initial debugging.
Build/Make Project – assembles and links (builds) files - only builds files that have changed since last build.
Rebuild Active Project – forces a build of all files and their dependencies
EE/CS-352: Embedded Microcontroller Systems

4. More details on the files generated
blink.wsp - project file
blink.asm  - source file
                 
blink.LST - list file
blink.OBJ - relocatable object file
                   
blink.M51 - linker map file
BLINK - absolute object file - program that gets downloaded
Linker map file (.M51) and absolute object file, are generated on each build/make, but they may be named with the base name of the first program compiled in a new project.
You can use the menu:
Project – Target Build Configuration
to set “absolute OMF file name” more appropriately.
It is not necessary to do that, but it is good to know what is going on.
EE/CS-352: Embedded Microcontroller Systems

5. EE/CS-352: Embedded Microcontroller Systems
Reset
Three ways to reset the processor:
When unconnected, press the reset button on the board.
When connected, press the RESET button on the IDE.
Watchdog timer overflow.
On reset, program execution starts here.
EE/CS-352: Embedded Microcontroller Systems

6. EE/CS-352: Embedded Microcontroller Systems
What Happens at Reset?
CPU halts operation
SFRs are initialized to default values
External pins set to a known state
Interrupts and Timers turned off
System clock defaults to 2MHz internal clock
PC reset
Watchdog timer set with longest timeout period
EE/CS-352: Embedded Microcontroller Systems

7. Ways of specifying HEX numbers in assembler code
0x prefix
Example: 0xF4
h suffix
Example: 33h
EE/CS-352: Embedded Microcontroller Systems

8. EE/CS-352: Embedded Microcontroller Systems
Watchdog Timer
21-bit timer runs off system clock (intially 2MHz)
Overflow of timer causes reset
Software must either disable watchdog timer, or periodically reset the timer so that it does not overflow
Timer can be “locked” to prevent disabling
EE/CS-352: Embedded Microcontroller Systems

9. More details of the Assembly process
The following code is produced in code memory by the assembler:
cseg at 0
mov a, #0
mov 0x30, a
mov DPTR, #0x445a
nop
Pages give the number of bytes per 8051 instruction for the C8051F020.
Address
Program Code
0000
74 99
0002
F5 30
0004 A
0007 00
EE/CS-352: Embedded Microcontroller Systems