TIC-TOC RTC by Computer and Technical Services
                                  Issue 2: 21/06/1988

N.B. The RTC unit MUST be in a higher priority socket than the DFS to respond correctly.
All commands may be prefixed with a 'Z'.

The Commands available in Tic-Toc are:
[CTRL+R+BREAK]       Resets the configuration data to default values (i.e. those which would
                      be expected if no RTC was fitted). This action MUST be undertaken when
                      Tic-Toc is first installed.
*SETTIME <time>      Sets the Time and Date - as Tue,24 May 1988.09:05:25
*RTC                 Displays current time on screen.
*NORTC               Switches OFF the Time display.
*NOCLOCK             Switches OFF the Time display, Alarm, Hell and Chime.
*BELL <time>         When <time> is reached the machine will beep until a key is pressed.
*CHIME               Causes a beep to be issued on the hour.
*NOCHIME             Switches OFF the hourly beep.
*ALARM <time>        When <time> is reached, a sequence of commands (defined by *BOOT) are
                      executed. If no (time) is given, the previous value is retained.
*BOOT <string>       Defines a sequence of actions which will be executed on [CTRL+BREAK],
                      *HARDBREAK and/or when the ALARM time is reached. Maximum length of
                      *BOOT is 30 characters. Control characters may be included - as with
                      programmable function keys.
*NOBOOT              Switches OFF the soft BOOT command.
*TIME                Prints the current Time and Date.
*DATE                Prints the current Date.
*PANEL               Enters Control Panel - to enable configuration.
*CONFIGURE <string>  Enables setting of the configuration value of <string>.
*STATUS              Displays a list of the current configuration settings, including the
                      various alarms.
*SHOW                Same function as *SHOW
*UNPLUG <number>     Turns OFF rom <number>.
*INSERT <number>     Turns ON rom <number>.
*GO                  Selects the Command Line Interpreter as the current language, using a
                     * prompt.
*CONSAVE <fsp>       Saves the configuration as a file on disk, in case of RTC RAM
                      corruption. If no <fsp> is specified, the configuration will be stored
                      as <CONDATA>.
*CONLOAD <afsp>      Load the configuration data into the RTC from the file <afsp>. If no
                      <afsp> is specified, the file <CONDATA> is assumed.

Uersion 2.03 of Tic-Toc has a number of features to extend even further its flexibility
 and compatibility with the BBC Master.

1) The *CONFIGURE TIME option (found in the Solidisk RTC rom) has now been implemented.
   This option will set the BBC micro's internal clock to the current value of the RTC -
   normally it is reset to zero by the OS on hard breaks. *CONFIGURE NOTIME can be used to
   deselect this option.

2) Unrecognised CONFIGURE commands are now sent to the paged roms using Service call &28.
   The first byte of the CONFIGURE 'name' is pointed to by (&F2),Y - as on the Master.

3) When Tic-Toc executes *STATUS or *SHOW, Service call &29 is also sent to the paged ROMs,
   so that they may print details of their own configuration settings. This duplicates the
   process found on the Master.

4) If the 'TT0k' string is NOT found in bytes 1-4 of the CMOS ram, Tic-Toc makes no attempt
   to configure the machine. *PANEL and *STATUS/*SHOW will therefore exit immediately, giving
   the error message 'CMOS Ram Unconfigured'.

Apart from giving added Master compatibility/emulation, 2 and 3 above also provide a route for
3rd party programmers to implement their own CONFIGURE commands, to save various flags or data
in the battery-backed ram on the RTC board.

Below is a memory map of the CMOS RAM, which, for most practical purposes, is the same as the
Master - apart from the soft boot string.

Byte    Usage
0       Various flags.
1-4     Tic-Toc presence string ("TT0k").
5       Default filing system and Language.
6-7     ROM unplugged/inserted flags.
8       Alarm, Bell, Chime, Soft boot On/Off flags.
9       Reserved for use by CaTS.
10      Screen mode, Shadow on/off, *TV setup.
11      ADFS and Keyboard setup, Floppy disk speed.
12      Keyboard auto repeat speed.
13      Keyboard delay rate.
14      Printer ignore character.
15      Printer type, RS423 baud rate, Tube on/off.
16      RS423 data mask, Shift boot on/off.
17-19   Reserved for use by CaTS.
20-49   Soft boot string.

Note: although Tic-Toc provisionally uses byte 20 onwards for storing the soft boot string,
these may be used by other applications if the soft boot option is switched off - which can
be checked for by examining byte 8.

The Acorn specification for bytes 20-49 is as follows:

20-29   Reserved for future use by Acorn.
30-45   For Sideways ROMs 0-15, one each, ROMNUM+30.
46-49   Available for individual user applications.

Tic-Toc implements the following OSWORDs and OSBYTES:

OSBYTE 161,X    Reads CMOS RAM byte X, returned in Y
OSBYTE 162,X,Y  Writes CMOS RAM byte X with data in Y
OSWORD 14       Read 24-byte RTC string to control block
OSWORD 15       Writes 8-byte time string at XY+1 in the format "09:05:25" or 24-byte RTC
                 string at XY+1 in the format "Tue,24 May 1988.09:05:25".