Lucent Technologies DSP1611, Information Manual

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Information Manual DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
April 1998 Serial I/O
Lucent Technologies Inc.
DRAFT COPY
7-17
7.6 Multiprocessor Mode Description
(continued)
7.6.2 Detailed Multiprocessor Mode Description
Three registers associated with multiprocessor mode are the time-division multiplexed slot (tdms) register (see
Table 7-5 ), the serial receive and transmit address (srta) register (see Table 7-6 ), and the serial input address
(saddx) register. Multiprocessor mode requires no external logic and uses a TDM interface with eight time slots
per frame. A serial address on the SADD line is sent simultaneously with data on DO from any one device in a pre-
determined time slot, and the data is received only by other device(s) having the address specified. Each device
has both a user-programmable receive address and transmit address associated with it.
In multiprocessor mode, the following pins are connected together to form a four-wire bus as shown in Figure 7-14 .
The DI and DO pins form a single-wire data bus referred to as DATA. ICK and OCK form a clock line referred to as
CK. SADD forms a single-wire address bus referred to as ADD. And, SYNC provides a synchronization line
referred to as SYN. Typically, one particular device is specified statically to always drive CK and SYN, although CK
can also be generated by an external clock. The signals are generated by the DSP device having active SYNC and
OCK signals that occur if the tdms register SYNC field is set and the sioc register OCK field is set.
5-4184
Figure 7-14. DSP1611/17/18/27/28/29 Multiprocessor Connections
The other devices use the SYNC and OCK signals in the passive mode to synchronize operations. All DSPs must
have their ILD and OLD signals in active mode. Although these signals are not required externally for the operation
of multiprocessor mode, they are used internally in the SIO and must be active for that reason.
DO ICK OCK ILD OLD IBF OBE SADD SYNC DOEN
DATA CK NC NC NC NC ADD SYN
DSP1611/17/18/27/28/29
NC
V
DD V
DD
DI