The ROM Memory Resident Monitor is responsible for providing the core IO and DISC interfaces required to the Single Board Computer.
For example all the XOP Defintions are defined, such as CALL, PUSH, POP, RET etc as well as all the interfaces routines required
to interface to a Western Digital type Floppy Disc Controller (FDC 1797), if implemented. The Disc IO provides a basic BIOS but relies on a
CP/M type DOS system to be fully functional.
The Monitor provides the following commands: (Q,O,[space],G,R,W,U)
Q(Quick Boot) This will boot the OS from the disc in drive 0
<TMS9900 DISC MONITOR V2.1>
>Q--Booting....
Shell Version 2.0
Release date 2 Oct 19
%
U(Upload) This command will upload a hex file into the TMS9900 SBC memory space. This is how the system files are created etc. Once the U command has been issued, go to your terminal and select the Hex file that you want to upload. The Upload command will sit forever waiting for the : colon to begin. Once received it will then handshake to upload the full file. For example:
<TMS9900 DISC MONITOR V2.1>
>U......................................................................................
O(Open) Will open or list of 8 rows displaying the memory contents begining at the HexAddress. Press Space to show the next 8 rows etc.
>C300O
C300 0460 C31A 0318 1319 1A20 0008 0D0A 07FF
C310 3A2E 2E2E 5F25 242A 2B00 02E0 CFA0 020A
C320 C2FE D820 C30C CC3A 0200 CC3A C800 00A0
C330 04E0 00A2 0200 CCA4 C800 00A4 0200 0460
C340 0201 C4CE C800 0080 C801 0082 0200 0460
C350 0201 D100 C800 0084 C801 0086 0200 0100
C360 C800 00A6 2FA0 CEAA C020 CC2E 04E0 CC2E
C370 C000 1616 04C1 D060 CC3A 9801 C30C 1310
(Space ) Will open the memory location for editing. Space will continue the editing to the next memory address
G(Go). Go will execute the memory based programme that is located at the HexAddress. So, you can use the Upload command to load the Shell, DOS etc and then use the Go command to run the disc initialisation or (DISKINIT) programme.
W(Workspace Register). This will enter the hexaddress into the workspace register and define your workspace. W by itself will print the value of current workspace register.
R(Registers). This command will print out the workspace registers located at the hexaddress, or will use the current workspace value. For example:
>>4R
WP=0004
R0 = DCA2 R1 = A8F9
R2 = ED20 R3 = F66A
R4 = ED30 R5 = F638
R6 = ED40 R7 = F66E
R8 = E8BD R9 = 26BD
R10 = C900 R11 = 703B
R12 = B235 R13 = 783D
R14 = 1185 R15 = E4E1
These basic commands are generally all that is required of a basic Monitor as the majority of all the other tasks can be use normal programmes and the Operating System.