NV9 Operations Manual GA326-4
19 of 38
© Copyright Innovative Technology Limited 2005
7.6 Multi-Drop Bus / Internal Communications Protocol (IF5) – MDB
To use the MDB mode an IF5 interface box must be fitted to the NV9 Validator and DIPswitches 3 & 4 must
both be set up, with the MDB option of the interface firmware loaded into the NV9.
Note:
§
Please refer to the Multi-Drop Bus specification for the suggested current drive circuits
available.
§
The NV9 supports the MDB protocol version 1, level 1
§
For detailed information and full protocol specification please refer to
MDB defines a serial bus interface used in electrically controlled vending machines (see figure 6). This is a
9600 Baud Master-Slave system where the NV9 banknote validator is a slave to a master controller. A master
has the capability of communicating with 32 peripherals or slaves. The master is defined as the Vending
Machine Controller (VMC).
Figure 6 – MDB Opto Isolated Input / Output circuits
The NV9 banknote Validators have a unique address – 00110XXX binary (30H). The VMC polls the bus to
detect presence of the NV9 Validators or get information on the current status of the Validators.
The Validators will respond when asked for activity with an acknowledgment, a negative acknowledgment or a
specific reply, depending on its current status. Bus crashes are avoided as the Validators respond to being
polled only by the VMC.
The international country code must be set for the country in which the Validators will be operating. This is the
international telephone code for that country. The code is represented as two bytes
For the USA the country code is 00 01
For Great Britain the code is 00 44
The scaling factor must also be specified for each Validator. All accepted note values must be evenly divisible
by this number.
•
This number would be set to 100 (Hex 64) for the Euro or Great Britain.
•
The number would be set to 1000 (Hex 03E8) for Romania.
•
The number of decimal places must also be programmed for each Validator
•
The number would be set to 2 for Euro or USA
•
The number would be set to 3 for Romania
Adopting the numbers above:
•
£5 would be displayed as 5.00
NV9 MDB Slave
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