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-
- Acorn Computers Ltd.
- British Broadcasting Corporation
- Master Series Microcomputer
-
- Functional differences between Master 128 and Models B & B+
-
- Operating system version:
- New Series 3 OS for the Master 128/512/Sc/Turbo
- New Series 4 OS for the Master Econet Terminal.
-
- Operating System changes:
- As version 1.2 with following extensions:
- * Shadow Screen - Use of MODE 128 to 135 instead of MODE 0 to 7
- results in the use of a section of memory for the screen separate
- from the main area of RAM. This allows more room for user Progs.
- * Real-time clock - the status of a Real-time clock can be called
- from the MOS. The OSWORD calls &E and &F Read & Write the clock
- in BCD or text formats.
- * Default command line interpreter if no language present or *GO
- used.
- * Configure CMOS RAM commands - the state of the CMOS RAM can be
- set for both reserved and unreserved Bits. Reserved Bits include:
- * Start-up mode MODE <0-7,128-135>
- * File-Server station number FS <0-255[.0-255]>
- * Printer-Server station number PS <0-255[.0-255]>
- * Econet station ID Transient Command
- (Must be set by Net Manager)
- * Start-up language ROM number LANG <ROM>
- * Start-up filing system ROM number FILE <ROM>
- * *TV position & Interlace state TV [<Dec>[,<Dec>]
- * Auto-repeat delay DELAY <0-255>
- * Auto-repeat rate REPEAT <0-255>
- * Default printer (*FX5 type) PRINT <0-255>
- * Print ignore char.(no param=no ignore)IGNORE <0-255>
- * Tube selected (Internal/External) EXTUBE/INTUBE
- (Looks for int Tube if no ext fitted)
- * Tube ON/OFF TUBE/NOTUBE
- (TUBE defaults to I/O Proc if no Co-proc fitted)
- * Serial baud rate (Both ways) BAUD <1-8>
- * Serial data format DATA <0-7>
- * Boot status BOOT/NOBOOT
- (Reverses BRK and SHIFT + BRK action)
- * Scroll state (on/off) SCROLL/NOSCROLL
- * Floppy-Drive params (speed etc) FDRIVE <0-3>
- (Use low number for highest step rate. 0 has MFM pre-
- compensation. 1 is same speed but no compensation)
- * Floppy or Winchester start-up FLOPPY/HARD
- (Floppy is selected if no Winchester fitted with HARD)
- * ADFS or FADFS as default DIR/NODIR
- (FADFS does not Mount disk automatically)
- * Bell character volume LOUD/QUIET
- * Caps lock on/off CAPS/NOCAPS/SHCAPS
- FS & PS status bits only operational when ANFS fitted.
-
- Configuration is set using *CONFIGURE <param> or read using
- *STATUS <param> or just *STATUS to read all.
- * Soft characters fully exploded
- * Improved soft-key structure with more buffer area.
-
- * New resident Operating System commands:
- *APPEND - functions as BUILD but appends to end of file.
- *BUILD - as DFS but control codes input by | mechanism.
- *CLOSE - closes open files on current filing system.
- *CONFIGURE - To set-up start-up option(s).
- *CREATE - creates empty file using *SAVE params.
- *DELETE - as DFS delete.
- *DUMP - <start in file> <start address on output>.
- *EX - Examine file in specified directory.
- *EXEC - Take input from file rather than keyboard.
- *GO - to enter address in language/IO processor.
- *GOIO - to enter program at address in IO processor.
- *IGNORE - as *FX6.
- *INFO - as *EX, but for single files or Wildcard use.
- *INSERT - inserts ROM number n into ROM map from reset.
- *LIST - List file in GSREAD format (*TYPE with line nos.)
- *LIBFS - Define FS where LIB is from current FS.
- *MOVE - copies files from one name to another incl
- between filing systems.
- *PRINT - as TYPE but gets/processes vdu codes.
- *REMOVE - as DELETE but no error msg if not found.
- *ROMS - lists ROM names, skts, vers & UNPLUG/PLUG.
- *SHADOW - with 0 or no param, gives shadow on next mode.
- With 1, drops shadow on next mode.
- *SHOW - Displays soft-key contents.
- *SHUT - Close open files on all filing systems.
- *SRDATA - Reserve Sideways RAM for data use.
- *SREAD - Copy Sideways RAM to main RAM.
- *SRROM - Reserve Sideways RAM for direct addressing.
- *SRWRITE - Copy main RAM to Sideways RAM.
- *SPOOL - Direct screen output to named file.
- *SPOOLON - functions as SPOOL but appends to end of file.
- *STATUS - Lists status of start-up option(s).
- *TIME - Displays time from Real-time clock.
- *TYPE - List file with control codes displayed as |D etc.
- *UNPLUG - removes ROM number n from ROM map from reset.
- * Numeric keypad - options to set base for range of values returned
- and set whether SHIFT/CTRL etc affect codes.
- * Cassette filing system upgraded to do OSGBPB (calls 1 & 3) in
- those cases where it is to write to or read from the current
- pointer.
- OSFSC extended for CFS to provide call 7 so that it returns
- legal file handle range.
- CFS will perform * EX ( but not * INFO ).
- CFS can be reselected by *FX143,18,<n> where n=1 (1200 baud),
- n=2 (300 baud, n=3 (ROM filing system),
- * Multifiling system capability. Name of filing system can be pre-
- fixed to the file name itself. Files may be opened and kept open
- across several filing systems.
- Filing names currently defined include:
- CFS (or TAPE), ROM, DFS, ADFS, NET
- * Extended graphics facilities:
- * Extended Fill commands using checkerboard pattern/stipple.
- * Mark-to-space ratio of dotted line.
- * New triangle algorithm for correct plotting under all
- conditions.
- * Parallelogram - Solid fill.
- * Rectangle - Solid fill.
- * Circle - Outline.
- * Circle - Solid fill.
- * Arc - Line fill.
- * Arc - Solid fill (Pie shape).
- * Arc - Solid fill (Chord segment).
- * Ellipse - Outline.
- * Ellipse - Solid fill.
- * Fill enclosing shape outline (flood-fill).
- * Enhanced speed of all fill operations.
- * Move/copy rectangle.
- * Extended horizontal line fill.
- * Extension text:
- * Improved character draw speed ( especially VDU5 ).
- * Clear block of text window.
- * Output character with no cursor move (dead key).
- * Advance left/right after drawing character.
- * Pending scroll to allow bottom right character to be
- drawn.
- * Cursor options held across mode changes.
- * Direct window scroll - left/right/up/down.
- * Extra 128 standard characters in ASCII range 128 to 255.
-
- Detailed changes:
- Miscellaneous:
-
- 1) Sideways ROM headers which have been "illegal" previously on Models B &
- B+, but accepted by the MOS, may not be accepted by this MOS version.
- 2) The screen Paged Mode algorithm has been improved in this MOS,
- resulting in slight differences in the number of displayed lines in some
- modes compared with Model B & B+.
- 3) In the Econet Terminal, the User VIA chip (6522) is not normally
- fitted. Application software intended for Econet use should not use the
- VIA timer.
- 4) The RAM latch at &FE34 has some changes and additions to the use of
- each bit. Refer to the Advanced Reference Guide for more information.
- 5) The machine start-up mode & language are now easily reconfigured. Soft-
- ware should always have an auto-boot file which sets the language and
- screen mode, without assuming a default state. (The machine may NOT be in
- Mode 7 or in BASIC at disk Boot-up).
- 6) Software should not use "*abbreviation" due to the risk of clashes with
- other fitted ROMs with similar *commands. In particular, *D. no longer
- selects the DFS! (It selects *DUMP).
- 7) Software should NEVER assume the position of PAGE. If it needs to know
- it should ask the operating system where OSHWM is.
- 8) To provide conversion compatibility across DFS & ADFS, note the
- following:
- *DRIVE - ADFS does not support this. Use *DIR :X.Y, which is a
- format common to both filing systems.
- *DIR - ADFS does not support moves directly from one directory
- to another, arbitrarily across the structure. Use the
- full pathname where relevant in DFS to support ADFS.
- 9) Programs should never define soft characters by directly loading into
- the soft-key definition area (&C00-&CFF).
- 10) The Econet Terminal is NOT upgradeable to other Master variants.
-
- Memory map changes
- The Shadow screen in the Model B+ from &3000 - &7FFF (Sideways) is present
- in the Master 128 machine. The 12K of additional Paged RAM in Model B+ is
- implemented differently in the Master 128 machine and is reserved for
- Operating and Filing system use as "Private RAM" (see below).
-
- The minimum machine configuration is 128K, where 64K is allocated to
- Sideways RAM (4 by 16K pages) in a similar way to the 128K Model B+. Use
- of internally fitted ROM's in two of the three sockets will require
- changes to the link settings which will remove access to some of the
- Sideways RAM. (They are ROM locations 4,5,6 & 7).
-
-
-
- Memory map below OSHWM, with changes from Model B/B+ indicated:
- Page zero - &00-&FF
- &00-&8F Language workspace. BASIC allows &70-&8F for the user.
- &90-&9F ECONET workspace. Do not use.
- &A0-&A7 NMI workspace. It must be claimed before use, the owner must:
-
- a) Have a Filing System number allocated to it. Note the error in
- the Advanced User Guide (Bray, Dickens & Holmes) on P. 323. The
- NMI ID passed around by Service Calls &B and &C are Filing
- System numbers not ROM numbers.
- b) Be able to process ROM Service Calls &B and &C i.e. they must be
- ROM's or intercept OSBYTE &8F.
-
- &A8-&AF MOS scratch space. Also user scratch between MOS calls.
- &B0-&BF Filing System scratch space. Watch out for "hidden" filing system
- calls i.e. those produced by OSWRCH if *SPOOL used.
- &C0-&CF Current Filing System PRIVATE workspace.
- &D0-&FF MOS workspace only (see Advanced Reference Guide, published by
- Acorn, for accurate decription of the VDU Driver use).
- Page one - &100-&1FF
- Machine stack and error message buffer.
- Page two - &200-&2FF
- &200-&235 Vectors.
- &236-&28F Main MOS variables.
- &290-&2FF MOS workspace (for MOS only).
- Page three - &300-&3FF
- &300-&37F VDU variables (for use by graphics routines only).
- In the Model B, B+ and this machine, Page three is used for VDU
- workspace. Most variables are the same, with the following exceptions:
- Model B & B+ This machine
- &359 - Foreground graphics colour Plotting foreground/background
- &35A - Background graphics colour Current graphics plot mode
- &366 - Mode 7 cursor Cursor control flags (VDU 23,16)
- &367 - Exploded font flag Dotted line pattern (VDU23,6)
- &368 - Exploded font location bytes Current dotted line state
- &369 - " " " " Plot colour (0-solid,Not 0-pattern)
- &36A - " " " " F/grnd col. (0-solid,Not 0-pattern)
- &36B - " " " " B/grnd col. (0-solid,Not 0-pattern)
- &36C - " " " " Col. 81 flag (top bit set pending)
- &36D - " " " " Foreground graphics colour
- &36E - " " " " Background graphics colour
- &380-&3DF Cassette Filing System workspace (do not use).
- &3E0-&3FF Keyboard input buffer (do not use unless replacing).
- Page four, five, six and seven - &400-7FF
- Language workspace. Do not use unless you are the current language or the
- current language has allowed you to use it.
- Page eight - &800-&8FF
- &800-&87F Sound workspace. DO NOT USE (unless you want strange noises!).
- &880-&8BF Printer buffer. Useable if, and only if, no printing needed.
- &8C0-&8FF Sound workspace (envelopes 1-4). Useable if, and only if,
- envelopes not needed.
- Page nine - &900-&9FF
- &900-&9BF RS 423 O/P buffer, or Cassette O/P buffer (1st part), or Sound
- workspace (envelopes 5 - 16). Do not use for anything else, as
- this area could be re-allocated.
- &9C0-&9FF Speech buffer, or Cassette O/P buffer (2nd part). Do not use
- for anything else, as this area could be re-allocated.
- Page ten - &A00-&AFF
- RS 423 I/P buffer, or Cassette I/P buffer. Do not use for anything else,
- as this area could be re-allocated.
- Page eleven - &B00-&BFF
- ECONET workspace. Do not use.
- In the Model B & B+ this is used for the soft key buffer. In this
- machine, the soft key buffer resides in the Private 12K RAM and should not
- be accessed by the user. Programs directly accessing Page eleven on the
- Model B & B+ for soft-key purposes will be incompatible with this machine
- Note: Initial Page states are:
- Model B, B+: &B00-&BFF - &10
- This machine: &B00-&BFF - &00
- Page twelve - &C00-&CFF
- ECONET workspace. Do not use.
- In the Model B & B+ this is used for user defined characters in the
- range ASCII 224-255. In this machine, all characters up to ASCII 255 are
- defined with a standard font. This definition resides in the Private RAM
- area and should not be accessed by the user (the user can, however,
- re-define all of them as before with VDU23). Programs directly accessing
- Page twelve on the Model B & B+ for user defined characters will be
- incompatible with this machine.
- Note: Initial Page states are:
- Model B, B+: &C00 - &0D &C01-&CFF - &00
- This machine: &C00-&CFF - &00
- Page thirteen - &D00-&DFF
- &D00-&D5F NMI routine and workspace. NMI's must be claimed to use this
- area.
- &D60-&D7F ECONET private workspace. Do not use.
- &D80-&D91 Currently unallocated.
- &D92-&D9E Reserved for Trackerball use.
- &D9F-&DEF Expanded vector set.
- &DF0-&DFF Paged ROM workspace, 1 byte per ROM.
-
- 12K Private RAM:
- &8000-&83FF Soft-key buffer. Do not use directly.
- &8400-&87FF VDU workspace. Reserved for routines that need a large area
- such as Flood-fill. Do not use directly.
- &8800-&88FF VDU variables and workspace. Do not use directly.
- &8900-&8FFF Character definitions. Do not use directly.
- &C000-&DBFF Paged ROM workspace, claimed via a Service Call.
- &DC00-&DCFF MOS CLI buffer. Corrupted by '*' commands.
- &DD00-&DEFF Transient utility workspace e.g. *MOVE.
- &DF00-&DFFF MOS private workspace.
-
- PCB Link settings:
- IMPORTANT!
- These links will not normally need adjustment. If they should require
- changing, the Mains Supply MUST be disconnected before removing the top of
- the computer case using the 4 screws on the underside marked FIX. Take
- note of any warning labels within the case.
-
- Link 1 - Audio to 1 Mhz. bus. Normally set for input. Can be changed to
- audio output by cutting track link A and linking B.
- Link 2 - Cartridge -5V decoupler. Fit R9 and break track link to enable
- capacitive decoupling within cartridge.
- Link 3 - Not present.
- Link 4 - Allocated for advanced software use. Enables real-time clock
- Alarm facility to be used. Not normally fitted.
- Link 5 - Sync polarity. Cut track link and join other side to invert
- from negative to positive sync.
- Link 60/61 - Normally AB only linked. Link CD in addition for 8 Mhz output
- to Cartridges.
- WARNING! The lack of a clock supply to the computer can cause
- damage to the computer's dynamic RAM. Link AB should not be
- removed as it would result in the loss of a clock supply.
- Link 7 - Video polarity. Cut track link and join other side to invert the
- video output.
- Link 8 - Not present.
- Link 9 - Not present.
- Link 10 - Channel select. Selects one of two VHF channels when VHF
- modulator fitted.
- Link 11 - Not present.
- Link 12 - Composite Sync output to Cartridge. Normally set to B. This
- provides a logic LOW at cartridge pin A10. In position A, a
- connection is provided to the computer CSYNC for GENLOCK.
- Link 13 - Change Link when fitting a different Reference Diode on the A/D
- input. This diode should be fitted at position PR1.
- Link 14 - Used when Chroma MSI chip not fitted.
- Link 15 - Select PAL or NTSC TV system encoding.
- Link 16 - Not normally fitted.
- Link 17 - Not present.
- Link 18 - Set East for ROM socket IC 41 active. Normally set West for
- sideways RAM active.
- Link 19 - Set East for ROM socket IC 37 active. Normally set West for
- sideways RAM active.
- Link 20 - Not present.
- Link 21 - Not normally fitted. Links Light-pen strobe into the
- intercartridge link pin 10. Can be used for Genlock sync via
- LPSTB.
-
- Cartridge sockets:
- The cartridge socket specification is a superset of the Electron Plus-1
- specification. All Electron Cartridges should work in this machine, but
- may run faster. The converse may not be true unless a specification
- sub-set is used. Ask for the new Cartridge Specification or consult the
- appropriate Reference Guide.
-
- For further technical information on the Master 128 machine, consult the
- following:
- Master Series Welcome Guide - Product Code ADJ01
- Master Series Reference Manual Part 1 - Product Code ADJ22
- Master Series Reference Manual Part 2 - Product Code ADJ23
- Master Series Advanced Reference Manual - Product Code ADJ24
-
- This information is subject to change without notice. No responsibility
- can be taken for any errors or omissions. The user or program writer
- should verify that any application program is suitable for the intended
- environment(s).
-
- DJBELL
-