Lucent Technologies DSP1611, Information Manual, Page: 242 / 443

DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR Information Manual
Parallel I/O (DSP1617 Only) April 1998
8-4
DRAFT COPY
Lucent Technologies Inc.
8.1 PIO Operation
(continued)
8.1.1 Active Mode (continued)
Active Mode Output
The DSP drives PODS and the PB.
The active mode output transaction (see Figure 8-3 ) is initiated by the DSP if it executes a data move to one of the
pdx channels (e.g., pdx0 = *r2). If an active mode output occurs, PSEL[2:0] are asserted to indicate which of eight
possible external devices will be the destination. One-half a CKO cycle later, the DSP pulls PODS low and places
data onto the PB. The duration of PODS is configurable in the pioc register (see
Table 8-1 ). The diagram below is
using minimum strobe widths, so PODS is held for one full CKO cycle. This data remains valid one-half of a CKO
cycle after PODS goes high.
5-4189
Figure 8-3. Active Mode Output Timing (Minimum Width PODS)
CKO
PSEL[2:0]
PODS
PB