III.1 Interactive Operation

BOOT-51 implements a simple ASCII user interface for serial communication. The bootstrap program can be operated interactively with a terminal emulation program running on the PC (e.g. TELIX under MS-DOS, or minicom under Linux). To perform this, start your terminal emulation program, and configure it for the correct baudrate, 8 data bits, 1 stop bit, no parity, and no handshake. Then reset the MCS-51 target system.
(If you have established an RS-232 reset line, the target system can usually be reset by dropping the RS-232 DTR output with the "hang-up" function!) Now the BOOT-51 sign-on message should appear on your screen:

BOOT-51  V1.1             Copyright (c) 2002 by W.W. Heinz

>

The '>' character indicates that the BOOT-51 command line interpreter is ready for input. It implements exactly two commands:

1. The UPLOAD command:
   First press the 'U', and then the return key.
   Now the upload prompt ':' should be displayed. BOOT-51 is now ready to receive an application program in Intel-HEX format. Send an Intel-HEX file with the ASCII upload function of your terminal emulation program. (Be sure that it terminates every line with a CR and/or LF character!) Now the received Intel-HEX records are loaded to their start addresses specified in the record headers. If an EOF record is received, the upload is terminated and the command prompt '>' is displayed again. Now the command line interpreter is ready for the next command.
   When a format error is detected in the Intel-HEX file, BOOT-51 waits until no more characters are received for about two seconds, and then aborts with a corresponding error message.   (see Appendix C)
    
2. The GO TO command:
   To start an application program at address 8000H, enter "G 8000" and press return. BOOT-51 sets now all MCU registers to reset conditions (as far as possible), and jumps to the start address specified. Now the previously loaded application program should be running!

Any desired number of Intel-HEX files may be loaded, before entering the 'G' command. The commands may be entered in upper or lower case letters. Interactive operation should be preferred, if the application program performs serial I/O. This can easily be supervised with the terminal emulation program. In interactive mode, only an RS-232 reset output is applicable. (A printer port reset cable would be of little use!)