But in addition it provides a simple command line interface to display or change memory contents or set, display or clear breakpoints. mon54.s19 is designed to support Eurocom II/V7 with a memory extension board. It has a FLEX boot loader and automatically boots FLEX if a disk is inserted in drive #0. Booting can also be started manually using command D. From within FLEX the monitor program can be entered by entering MON on the FLEX prompt. From the monitor program FLEX can be reentered with G CD03.
This documentation describes the monitor programs V5.3 and V5.4 as deployed with flexemu as files mon53.s19 and mon54.s19. Both provide the same functionality. The only difference is that V5.4 needs and only works with a RAM extension while V5.3 does not support a RAM extension. Any command has to be entered in uppercase characters.
This monitor program overview shows which monitor program is best suited for which hardware configuration.
The following table gives an overview of the available commands:
Command | Description |
---|---|
A | Display and optionally modify CPU registers. Can be aborted by entering ESC. See also command B, C, K or S. |
B XXXX | Set breakpoint at address XXXX. Up to eight breakpoints can be defined. Only supported for an address located in RAM, so it does not work for address range F000 up to FFFF. At address 0000 no breakpoint can be set. See also command A, C, K or S. |
B ENTER | Display address of all eight breakpoints. |
C | Continue programm execution at current PC location. Any CPU register, incl. PC can be changed with command A in between. See also command A, B, K or S. |
D | Boot from disk in drive #0. |
E | Empty command, just reenters the command prompt. |
G XXXX | Jump to address XXXX. |
K XXXX | Remove breakpoint at address XXXX. If there is no breakpoint set at this address BRP is printed. See also command A, B, C or S. |
L | Load a file in Motorola S-Record format from serial port. This can be used with flexemu on Unix like operating systems by redirecting stdin to a S-Record file when starting flexemu on the command line. See also command R. |
CTRL-L | Clear screen. |
M XXXX | Display and modify memory at address XXXX.
. Redisplay contents of current address (Try with address FD00, it displays the actual seconds of the real time clock). CTRL-J or / Display contents of next address. ^ Display contents of previous address. ZZ Entering a two digit hex number changes the memory at current address. ENTER or CTRL-X Leaving M command. |
O XXXX YYYY | Calculate address offset for a MC6809 branch or long branch operation. |
R XXXX YYYY | Write a file in Motorola S-Record format to serial port for the given address range incl. address YYYY. This can be used with flexemu on Unix like operating systems by redirecting stdout into a S-Record file when staring flexemu on the command line. See also command L. |
S | Command S: Step over a breakpoint. See also command A, B, C or K. |
T XXXX YYYY | Memory dump from XXXX to incl. YYYY. |
V | Terminal mode: Any input and output is sent or received from or to serial port. |
. | Continue displaying memory content of current address based on a previous M command or address 0000. |
CTRL-J or / | Continue displaying memory content of next address based on a previous M command or address 0000. |
^ | Continue displaying memory content of previous address based on a previous M command or address 0000. |
ZZ: | A two digit hex number. |
XXXX or YYYY: | A four digit hex address. |
Monitor program V5.3 and V5.4 also contain a terminal emulator which can be controlled with the following Control- and Escape-sequences:
Control character |
Description |
---|---|
CTRL-B or CTRL-L | Form feed, clear screen, cursor home |
CTRL-G | give a short terminal bell |
CTRL-H | Backspace |
CTRL-J | Linefeed |
CTRL-M | Carriage return |
CTRL-Q | Cursor up one line |
CTRL-R | Cursor down one line |
CTRL-S | Cursor right one character |
CTRL-T | Cursor left one character |
ESC or CTRL-[ | Start ESCAPE sequence |
CTRL-] | Toggle between soft- and hard scroll |
The following Escape sequences are available:
ESC sequence | Description |
---|---|
ESC A XX YY | Plot a dot |
ESC E Y X | Set cursor to line Y and column X. X and Y have an offset of $20 |
X or Y: | Any charcter. |
XX or YY: | Any two characters. |