Model 100 System Map Part 0: Difference between revisions
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* Microsoft BASIC Decoded & other Mysteries for the TRS-80, by James Lee Farvour, IJG (December 1982) | * Microsoft BASIC Decoded & other Mysteries for the TRS-80, by James Lee Farvour, IJG (December 1982) | ||
* "Inside the 100", by David P. Sumner, 80 Micro (December 1983) | * "Inside the 100", by David P. Sumner, 80 Micro (December 1983) | ||
[[Category:Model T Developer Reference]] [[Category:Model 100 System Map]] | |||
Revision as of 09:39, 1 April 2009
Origin
This is a derived work of the "Model 100 System Map", Copyright (C) 1985, Robert D. Covington, Systems Information Management Consultants.
File Formats
.BA Files:
2 bytes - Address of next line
2 bytes - Line number
Up to 255 characters ending with a null
EOF is 3 consecutive nulls
.DO Files:
Text ended with a EOF character 1AH
.CO Files:
2 bytes - Address to load to
2 bytes - Number of bytes to load (-start 6)
2 bytes - Transfer address
File Descriptor Block Format
The File Descriptor Block is the address given by VARPTR(#file).
Byte:
0 - File status (0-not open, 1-open for input, 2 open for
output or append)
2 & 3 - Address of file directory entry
4 - File device (248-RAM, 249-MoDeM, 250-LinePrinTer,
251-WAND, 252-COM, 253-CASsette, 254-CRT, 255-LCD)
6 - Offset from buffer start (see bytes 9) for start of next
record
7 & 8 - Relative position of next 256 byte block from
beginning of file
9 - Start of 256 byte buffer for data transfer
Floating Point Accumulator Format
---------------------------------------------------------------
FAC1 | FAC2 | DP | SP | Integer | SP
Address | Address | Format | Format | Format | Register
---------------------------------------------------------------
FC18H | FC69H | S & E | S & E | - | C
FC19H | FC6AH | BCD M | BCD M | - | B
FC1AH | FC6BH | BCD # | BCD # | LSB | E
FC1BH | FC6CH | BCD # | BCD L | MSB | D
FC1CH | FC6DH | BCD # | - | - | -
FC1DH | FC6EH | BCD # | - | - | -
FC1EH | FC6FH | BCD # | - | - | -
FC1FH | FC70H | BCD L | - | - | -
---------------------------------------------------------------
LSB = Least significant byte of intger
MSB = Most significant byte of integer. Bit 7 contains the sign
of the integer
BCD L = Least significant BCD byte
BCD H = Most significant BCD byte
BCD # = Middle BCD bytes. Each digit of the number is represented
by one of the values in the two nibbles in each byte
S & E = Sign and exponent of each number. Bit 7 contains the sign
of the floating point number. Bit 6 must be set. Bits 0-5
determine where the decimal point is to be inserted. For
example, if this byte contained a 65, the sign would be
positive and the decimal point would be placed between the
first and second digits (#.###....)
Option ROM Important Addresses
40H = 54H 41H = 43H - Required for ROM to be detected on BOOT 42H - 47H - Name of file associated with ROM program Code at 7E24H-7E43H executed on BOOT to handle option ROM. Code at 0365H loaded at F605H on BOOT to detect option ROM.
Model 100 Hardware Port Map
A0H - Modem control port
Output:
Bit:
0 - Modem telephone relay (1-Modem connected to phone
line)
1 - Modem enable (1-Modem chip enabled)
B0H - 8155 PIO Command/Status Register
Output:
Bit:
0 - Direction of Port A (0-input, 1-output)
1 - Direction of Port B (0-input, 1-output)
2 & 3 - Port C definition (00 - All input, 11 - All output,
01 - Alt 3, 10 - Alt 4 (see Intel technical sheets
for more information))
4 - Enable Port A interrupt (1 - enable)
5 - Enable Port B interrupt (1 - enable)
6 & 7 - Timer mode (00 - No effect on counter, 01 - Stop
counter immediately, 10 - Stop counter after TC, 11
- Start counter)
Input:
Bit:
0 - Port A interrupt request
1 - Port A buffer full/empty (input/output)
2 - Port A interrupt enabled
3 - Port B interrupt request
4 - Port B buffer full/empty (input/output)
5 - Port B interrupt enabled
6 - Timer interrupt (status of TC pin)
7 - Not used
B1H - 8155 PIO Port A
Output:
8 bit data port for printer output, keyboard column strobe,
and LCD
In addition, the first 5 bits of this port is used to
control the 1990 real time clock chip. The configuration of
these five bits are:
Bit:
0 - C0
1 - C1
2 - C2
3 - Clock
4 - Serial data into clock chip
B2H - 8155 PIO Port B.
Output:
Bit:
0 - Column 9 select line for keyboard. This line is
also used for the CS-28 line of the LCD.
1 - CS 29 line of LCD
2 - Beep toggle (1-Data from bit 5, 0-Data from 8155
timer)
3 - Serial toggle (1-Modem, 0-RS232)
4 - Software on/off switch for computer
5 - Data to beeper if bit 2 set. Set if bit 2 low.
6 - DTR (not) line for RS232
7 - RTS (not) line for RS232
B3H - 8155 PIO Port C
Input:
Bits:
0 - Serial data input from clock chip
1 - Busy (not) signal from printer
2 - Busy signal from printer
3 - Data from BCR
4 - CTS (not) line from RS232
5 - DSR (not) line from RS232
6-7 - Not avaiable on 8155
B4H - 8155 Timer register. LSB of timer counter
B5H - 8155 Timer register. MSB of timer counter
B8H - Same as port B0H
B9H - Same as port B1H
BAH - Same as port B2H
BBH - Same as port B3H
BCH - Same as port B4H
BDH - Same as port B5H
C0H - Bidirectional data bus for UART (6402) (C0H-CFH same)
D0H - Status control register for UART, modem, and phone (6402)
(D0H-DFH same)
Output:
Bits:
0 - Stop Bits (1-1.5, 0-2)
1 - Parity (1-even, 0-odd)
2 - Parity Enable (1-no parity, 0-parity enabled)
3 - Data length (00-5 bits, 10-6 bits, 01-7 bits, 11-8
bits)
4 - Data length (see bit 3)
Input:
Bits:
0 - Data on telephone line (used to detect carrier)
1 - Overrun error from UART
2 - Framing error from UART
3 - Parity error from UART
4 - Transmit buffer empty from UART
5 - Ring line on modem connector
6 - Not used
7 - Low Power signal from power supply (LPS not)
E0H - Keyboard input and misc. device select (E0H-EFH same)
Output:
Bits:
0 - ROM select (0-Standard ROM, 1-Option ROM)
1 - STROBE (not) signal to printer
2 - STROBE for Clock chip (1990)
3 - Remote plug control signal
Input:
8 bit data row from keyboard strobe
F0H - LCD display data bus (F0H-FFH same)
Model 100 Keyboard Matrix
------------------------------------------------
7 | L K I ? * -> Ent f8 Brk
Row 6 | M J U > & <- Prt f7
In 5 | N H Y < ^ Up Lbl f6 Cap
4 | B G T " % Dwn Pst f5 Num
0E0H- 3 | V F R : $ + Esc f4 Cde
0EFH 2 | C D E ] # - Tab f3 Gph
(224- 1 | X S W P @ ) Del f2 Ctl
239) 0 | Z A Q O ! ( Spc f1 Sft
------------------------------------------------
bit 0 1 2 3 4 5 6 7 0
[----------- 0B1H or 0B9H -----------] [0B2H]
[----------- 177 or 185 ------------] [178 ]
Column Strobe
Note: This table is incorrectly documented in Radio Shack's
"Model 100 Technical Reference Manual" (26-3810)
Math Routine Summary
-------------------------------------------------------------
Function Single Precision Double Precision Integer
-------------------------------------------------------------
+ 37F4H 2B78H 3704H
- 37FDH 2B69H 36F8H
* 3803H 2CFFH 3725H
/ 380EH 2DC7H 0F0DH
^ 3D7FH 3D8EH 3DF7H
Compare 3498H 34FAH 34C2H
-------------------------------------------------------------
RIM and SIM Bit Maps
SIM Bit 0: RST 5.5 mask (set mask) RIM Bit 0: RST 5.5 mask
1: RST 6.5 mask (set mask) 1: RST 6.5 mask
2: RST 7.5 mask (set mask) 2: RST 7.5 mask
3: Mask set enable 3: Int. enable
4: Reset RST 7.5 flip/flop 4: RST 5.5 pending
5: Not used 5: RST 6.5 pending
6: SOD change enable 6: RST 7.5 pending
7: SOD pin output 7: SOD pin input
Note: SOD pin is used for cassette I/O on Model 100
Model 100 Special Control Characters
--------------------------------------------------------------
Control Code | Print | Routine |
Sequence | Address | Address | Description
--------------------------------------------------------------
Beep (7) 4229H 7662H Beep
Tab (9) - 4480H Tab cursor
LF (10) 4225H 4494H Move down one line
Home (11) 422DH 44A8H Home cursor
CLS (12) 4231H 4548H Clear screen
CR (13) - 44AAH Move cursor to beginning of
next line
ESC A - 4469H Move cursor up one line
ESC B - 446EH Move cursor down one line
ESC C - 4453H Move cursor to the right
ESC D - 445CH Move cursor to the left
ESC E - 4548H Clear screen
ESC H - 44A8H Home cursor
ESC J - 454EH
ESC K 425DH 4537H Erase from the cursor to the
end of the screen
ESC L 4258H 44EAH Insert blank line at current
line
ESC M 4253H 44C4H Delete current line
ESC P 4249H 44AFH Turn cursor on
ESC Q 424EH 44BAH Turn cursor off
ESC T 4235H 4439H Protect line 8
ESC U 423AH 4437H Unprotect line 8
ESC V 423FH 443FH Stop automatic scrolling
ESC W 4244H 4440H Resume automatic scrolling
ESC X 4262H 444AH
ESC Y 427CH 43AFH Set cursor position.
Coordinate for cursor (row
and column) follow ESC Y
sequence
ESC j - 4548H Clear screen
ESC l - 4535H Erase current line
ESC p - 4431H Start inverse video mode
ESC q - 4432H Cancel inverse video mode
History
This documented was created with well over 200 hours of sweating over a Model 100 ROM disassembly. I started my first research on the Model 100 ROM about 2 hours after purchasing it (Note: I had one of the first 100's off the production line. I believe I purchased my 100 in June of 1983). After I figured out how to use TELCOM, I downloaded a BASIC Z-80 disassembler that friend of mine (Mike Livorsi) wrote from my Model 3. After making a few changes to the disassembler, I was able to get it to work on the Model 100. Then, I tested my Model 100's parallel printer port by printing a disassembly of the Model 100's ROM on my old LP8 (note:the disassembly requires a 3 inch note book to fit in). A day later, I came back to my Model 100 and found what every machine language addict loves; a complete dissasembly of the ROM.
At this point, I had a big problem; where to start. At the time, the only documentation for the 100 was the Instruction Manual. "Hacker reliefs" like schematics, memory maps, debuggers, etc. could only be found in the dreams of the infant portable hackers.
What did I end up doing? Well, I decided to write a little BASIC program to search for specific bytes in ROM. This program was used initially for finding the text string "Ok" in ROM. Once I found out where the message was in ROM, I then searched for any ML instructions that referenced the message. Then, on a warm July night in St. Louis, I found what I was looking for; a 16 bit register load that referenced the message "Ok" followed by a CALL instruction. This was the key I needed to open the door to the Model 100's ROM. With my experience from the Model 1/3/Coco ROMs, I knew that the load/CALL sequence I found was used to print a text string on the screen. From this little information, I was able to interrogate the subroutine called and find out how the display operated. In addition, since "Ok" is only printed at BASIC ready, I was able to trace out the keyboard input routines and eventually, the entire BASIC interpreter.
About 200 or so hours later, I documented most of the Model 100's ROM. At this time, I knew enough about my Model 100 to write just about any machine langauge program that I needed.
When I started writing ML programs for the 100, I found one problem with my ROM documentation; it was too hard to find a particular ROM address. What I needed was an organized collection of all my notes, "chicken scratches", etc.
From this came the memory map you hold in your hand right now. In this memory map, I basically included the information that I use the most when ML programming. I did not include a lot of information on how the ROM handles certain task, but I did include information that can be used by external stand alone ML programs.
References
In creating this document, I had a little help along the way with figuring out a few things. Below is a list of sources I used to help me determine or verify what certain things in the Model 100 did:
- Model 100 User Manual, Radio Shack
- Model 100 Service Manual (26-3801), Radio Shack
- Microsystem Components Handbook, Volume 1, Intel (1984)
- MOS Microprocessors and Peripherals, Advanced Micro Devices (1983)
- Microsoft BASIC Decoded & other Mysteries for the TRS-80, by James Lee Farvour, IJG (December 1982)
- "Inside the 100", by David P. Sumner, 80 Micro (December 1983)
