DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
Information Manual
Parallel Host Interface (PHIF) (DSP1611/18/27/28/29 Only)
April 1998
9-6
DRAFT COPY
Lucent Technologies Inc.
9.1 PHIF Operation
(continued)
9.1.4 Motorola Mode, 16-Bit Write
The external device drives PCSN, PIDS/PRWN, PODS/PDS, PBSEL, and PB.
In
Motorola mode, PIDS is renamed PRWN (parallel read/write not) and selects a read or a write. PODS is
renamed PDS and is the data strobe for both input and output.
Initially, PB is 3-stated. The write mode is selected if PIDS/PRWN is low, and the write is initiated by either PCSN
or PODS/PDS. Data is enabled into the DSP if both PCSN (chip select) and PODS/PDS (input data strobe) are
low. The timing of this action is controlled by whichever of the two goes low last. PBSEL (byte select) is low, so the
data is transferred to the low byte of the pdx0(IN) register. If PODS/PDS is driven high by the external device, the
data is latched by the DSP. The timing of this action is controlled by PODS/PDS or PCSN, whichever goes high
first. PBSEL can now be driven high to select the high byte of pdx0(IN). The sense of PBSEL and PODS/PDS can
be reversed by programming the phifc register. The default state is shown here. The cycle is completed by
another strobe from PCSN and PODS/PDS. After the rising edge of PODS/PDS latches the high byte into the DSP,
the PIBF interrupt is generated and the PIBF output pin goes high. The PIBF interrupt is reset when the DSP reads
pdx0(IN).
† The logic levels of these pins can be inverted by programming the phifc register.
5-4498
Figure 9-5. Motorola Mode, 16-Bit Write
PCSN
PIDS/PRWN
(CHIP SELECT)
PODS/PDS
†
, FROM
EXTERNAL DEVICE
PB, FROM
PIBF
†
PBSEL
†
LOW BYTE WRITE
HIGH BYTE WRITE
EXTERNAL DEVICE
Содержание DSP1611
Страница 18: ...Chapter 1 Introduction...
Страница 27: ...Chapter 2 Hardware Architecture...
Страница 52: ...Chapter 3 Software Architecture...
Страница 116: ...Chapter 4 Instruction Set...
Страница 154: ...Chapter 5 Core Architecture...
Страница 176: ...Chapter 6 External Memory Interface...
Страница 208: ...Chapter 7 Serial I O...
Страница 237: ...Chapter 8 Parallel I O DSP1617 Only...
Страница 261: ...Chapter 9 Parallel Host Interface PHIF DSP1611 18 27 28 29 Only...
Страница 275: ...Chapter 10 Bit I O Unit...
Страница 284: ...Chapter 11 JTAG Test Access Port...
Страница 306: ...Chapter 12 Timer...
Страница 313: ...Chapter 13 Bit Manipulation Unit...
Страница 325: ...Chapter 14 Error Correction Coprocessor DSP1618 28 Only...
Страница 350: ...Chapter 15 Interface Guide...
Страница 367: ...Appendix A Instruction Encoding...
Страница 379: ...Appendix B Instruction Set Summary...
Страница 381: ...aD extractz aS IM16 B 52 aD insert aS arM B 53 aD insert aS IM16 B 54 aD aS aaT B 55...
Страница 437: ...Index...