SAA2501 Datasheet, PDF (34/52 Pages) NXP Semiconductors – Digital Audio Broadcast DAB decoder

Philips Semiconductors
Digital Audio Broadcast (DAB) decoder
Preliminary specification
SAA2501
During operation 2 modes can be identified:
1. Addressing mode (AM).
During addressing mode a single byte is sent by the microcontroller. This byte consists of 2 data operation mode
(DOM) bits and 6 operational address (OA) bits. Each of the slave devices evaluates the operational address. Only
the device that has been issued the same operational address will become active during the following data mode.
The operation to be executed during the data mode is indicated by the two data operation mode bits.
2. Data mode (DM).
During data mode information is transferred between microcontroller and slave device. The transfer direction may
be from microcontroller to slave (‘write’) or from slave to microcontroller (‘read’). However, during one data mode the
transfer direction cannot change.
8.1.1.1 Addressing mode
In order to start an addressing mode the microcontroller will make the L3MODE line LOW. The L3CLK line is put to the
LOW state 8 times and the DATA line will carry 8 bits. The addressing mode is ended by making the L3MODE line HIGH.
ha_Ln₃db_Mo_Ook_D, h_Ealfpage
L3CLK
L3DATA
012345 6 7
MGB505
The meaning of the bits on L3DATA.
Bit 0 and bit 1; these are the data operation mode (DOM) bits that indicate the nature of the following data transfer. Each slave device may have
its own allocation of operation modes to the 4 possible codes of these bits. For correct information about the operation the device will perform, refer
to the descriptions of the individual ICs. For new designs the preferred allocations are given in Table 35.
Bit 2 to bit 7; these bits act as 6 bit (special function) operational IC address, with bit 7 as MSB and bit 2 as LSB. Bit 7 to bit 5 act as system
identification and bit 4 to bit 2 as identification of the device within the system.
Fig.16 Addressing mode.
Table 35 Preferred allocations
DOM1
0
0
1
1
DOM0
0
1
0
1
FUNCTION
data from microcontroller to SAA2501
data from SAA2501 to microcontroller
control from microcontroller to SAA2501
status from SAA2501 to microcontroller
REMARKS
general purpose data transfer
general purpose data transfer
e.g. register selection for data transfer
short device status message
January 1995
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