SAA2501 Datasheet, PDF (36/52 Pages) NXP Semiconductors – Digital Audio Broadcast DAB decoder

Philips Semiconductors
Digital Audio Broadcast (DAB) decoder
Preliminary specification
SAA2501
8.1.3.1 Operational address declaration
For the declaration (programming) of the operational
address of an L3 device with a ‘secondary L3 identification
code’ the following actions are required:
1. First the microcontroller must issue an L3 operational
address ‘000000’ (special function address) with
DOM1 = 0 and DOM0 = 1. This combination defines
the operational address declaration operation. Next
the microcontroller will start a data transfer mode in
which it first sends the secondary L3 identification
code for the device that is to be issued an operational
address, followed by a byte containing the operational
address (the DOM bits in this byte are don't cares).
2. Next the microcontroller will start a data transfer mode
in which it first sends the secondary L3 identification
code for the device that is to be issued an operational
address, followed by a byte containing the operational
address (the DOM bits in this byte are don't cares).
A secondary L3 identification code is unique for any
design. Devices of the same design have the same
identification code of one or more bytes. However, special
designs may have a range of identification codes, one of
which can be selected by a hardware solution, to enable
the connection of more than one device of the same
design to the L3 interface. It is also possible to use
separate L3MODE lines for multiple devices of the same
design, but the same L3 identification code (this also
enables ‘parallel programming’ of these devices). Bit 0 of
any identification code byte will indicate whether or not an
additional byte follows:
Bit 0 = 0; no additional byte as part of the identification
code.
Bit 0 = 1; additional byte follows.
With this the number of secondary L3 identification codes
is (theoretically) unlimited.
The operational address for the programmable device is
preferable in the range 111000 to 111111. However, it is
possible in a given application to issue any operational
address that is not used to address primary L3 devices or
other secondary L3 devices. An example is given in
Table 36.
Table 36 Example of L3 devices; notes 1 to 4
ADDRESSING MODE
DATA MODE
SPECIAL ADDRESS
SECONDARY L3 IDENTIFICATION CODE
BYTE 1
BYTE 2
BYTE 3
10000000
1XXXXXXX
1XXXXXXX
0XXXXXXXX
OPERATIONAL
ADDRESS
(ONE BYTE)
MMYYYYYY
Notes
1. Bits are shown in the order they appear on L3DATA (bit 0 first, bit 7 last).
2. X = bit of the identification code.
3. M = DOM bit of operational address (don’t care).
4. Y = bit of the operational address.
8.1.3.2 Operational address invalidation
In order to re-allocate an operational address that has been allocated to a secondary L3 device it is possible to invalidate
an operational address:
• First the microcontroller must issue an L3 operational address ‘000000’ (special function address) with DOM1 = 1 and
DOM0 = 0. This combination defines the operational address invalidation operation.
• Next the microcontroller will start a data transfer mode in which it only sends the secondary L3 identification code for
the device that will no longer be addressed. From this moment on the device will not be able to communicate with the
microcontroller until it is issued a new operational address by an OA declaration (it will enter a ‘device interface reset’
condition).
Remark: the combination of a special function address (000000) and DOM1 and DOM0 equal to ‘1’ is reserved for future
applications. Designs based on this specification will react with a ‘device interface reset’.
January 1995
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