Note on Uwatec MemoMouse (DOS Version) for Aladin Dive Computers

MemoMouse (DOS version) and PC are physically connected by Uwatec DOS cable, which is also usable to connect Aladin and PC directly. This means that two types of connections between PC and Aladin are possible and supported by DataTrak for DOS.

Type 1. Direct connection:
         Aladin  --[Uwatec DOS cable]-->  PC

Type 2. Connection via Memomouse/DOS:
         Aladin  --> Memomouse/DOS <--[Uwatec DOS cable]--> PC

In order to maintain compatibility to these two connections, DataTrak/DOS firstly sets PC's serial port to

   19200 baud, 8 bits, No parity and 1 stop bit, No hardware flow control,

and listens the port. This is the same setting for Uwatec DOS cable (or DIY Aladin I/F) without Memomouse/DOS by using as connection Type 1 above.

Initiation of one data transfer is always done by touching Aladin's contacts (or by Aladin in SOS mode) and cannot be done by PC. Thus, to notify PC that Memomouse/DOS wants to send dive data, a consecutive four characters sequence

                       ccc\0

(three ASCII character c's followed by one null character) is sent to PC.

Note: If the four character sequence "UUU\0" is received by PC then the Uwatec DOS cable is directly connected to Aladin (not via Memomouse/DOS).

After the sequence "ccc\0", Memomouse/DOS and DataTrak/DOS changed the serial communication setting to

   4800 baud, 8 bits, No parity and 1 stop bit, No hardware flow control.

In this communication speed,

       1. DataTrak/DOS send one byte 0xAA (bit reversal of ascii 'U'),  
       2. And Memomouse/DOS send back one byte 0x60 (bit reversal of ACK).

After this, they reset the serial speed to

   19200 baud, 8 bits, No parity and 1 stop bit, No hardware flow control

again, and DataTrak/DOS listens/waits the port for a data packet, which consists of length of data, data, and checksum.

To summarize the above negotiation procedure, the full protocol is illustrated in the following diagram:

PC (DataTrak/DOS)                             Memomouse/DOS
-----------------------------------------------------------------------
Prepare to receive
(Push F5).

                                              Touch Aladin's contacts and
                                              change [logbook] to [logbook1].
                                              If data transfer from Aladin to
                                              Memomouse/DOS is successful then 
                                              green LED is lit, and ...
                          baud := 19200
                        <-------------------  ccc\0
(*)
                          baud := 4800
0xAA (reversal of 'U')   ------------------->
                        <-------------------  0x60 (reversal of ACK)

                          baud := 19200
                        <-------------------      Dive data packet

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