
DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
Information Manual
Parallel I/O (DSP1617 Only)
April 1998
8-20
DRAFT COPY
Lucent Technologies Inc.
(continued)
Bits 4—0 of the pioc indicate whether an interrupt was generated by IBF, OBE, PIDS, PODS, or INT0. These bits
can be read by an interrupt service routine to determine which interrupt(s) have occurred and, hence, how to pro-
ceed to service the interrupt request. These status bits are also used to perform programmed I/O by polling some
conditions when necessary. It is important to note that pending interrupt status bits are cleared under the following
conditions:
IBF (pioc[4]) indicates that the serial I/O input buffer is full. It is cleared by reading from the sdx (serial I/O) reg-
ister.
OBE (pioc[3]) indicates that the serial output buffer is empty. It is cleared when a write to the sdx (serial I/O) reg-
ister is performed.
PIDS (pioc[2]) indicates that an external device has written into the DSP's PIO register. Reading from the PIO
register (pdx0 through pdx7), either inside or outside an interrupt routine, clears this bit. This interrupt can occur
only if the DSP is in the passive mode; accordingly, the DSP reading from the PIO registers to clear pioc[2] does
not cause an external read transaction to take place.
PODS (pioc[1]) indicates that an external device has read from the DSP's PIO register. Writing to the PIO regis-
ter (pdx0 through pdx7), either inside or outside an interrupt routine, clears this bit. This interrupt can occur only
if the DSP is in the passive mode; accordingly, writing to the PIO registers (to clear pioc[1]) does not cause an
external write transaction to take place.
INT0 (pioc[0]) indicates that an external device has asserted the INT0 signal. It is cleared when the interrupt
acknowledge (IACK) signal makes a high-to-low transition indicating that the interrupt service routine has
completed. If external interrupts are masked, this bit will not be set if INT0 is asserted. This bit can be cleared
only if an ireturn instruction causes the high-to-low transition of IACK.
Note: There is a latency of one instruction cycle if altering the INTERRUPTS field of the pioc register. For exam-
ple, if interrupts are disabled with the command pioc = 0x00, the DSP still responds to an interrupt during
the next instruction. After this instruction is executed, the interrupts are disabled. Therefore, to protect an
instruction sequence from interrupts, follow the command to mask the INTERRUPTS field of the pioc regis-
ter with one instruction that can be safely interrupted.
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...