
Philips Semiconductors
PCI Interface
PRODUCT SPECIFICATION
11-15
is decremented, and this sequence repeats until TL
reaches ‘0’.
At the end of the PCI
→ SDRAM block transfer, the PCI
interface will generate a DSPCPU interrupt if the appro-
priate IntE bit is set in BIU_CTL. Alternatively, DSPCPU
software can poll the appropriate ‘done’ status bit in
BIU_STATUS.
During an SDRAM
→ PCI block transfer, the PCI inter-
face drives the address from SRC_ADR to the SDRAM
controller. The returned data is buffered in w_buffer. The
PCI interface then drives the address from DEST_ADR
and the data from w_buffer to the PCI bus. SRC_ADR
and DEST_ADR are incremented, the TL field in
DMA_CTL is decremented, and this sequence repeats
until TL reaches ‘0’.
At the end of the SDRAM
→ PCI block transfer, the PCI
interface can generate a DSPCPU interrupt if the appro-
priate IntE bit is set in BIU_CTL. Alternatively, DSPCPU
software can poll the appropriate ‘done’ status bit in
BIU_STATUS.
11.7.17 INT_CTL Register
The INT_CTL register contains three fields for setting,
enabling, and sensing the four PCI interrupt lines.
Table 11-19 shows the interpretation of the fields in
INT_CTL.
INT (Interrupt bits). The INT field (bits 0..3 of INT_CTL)
can force a PCI interrupt to be signalled.
IE (Interrupt enable). The IE field (bits 4..7 of INT_CTL)
enables TM1300 to drive PCI interrupt lines.
IS (Interrupt state). The IS field (bits 8..11 of INT_CTL)
senses the state of the PCI interrupt lines.
Figure 11-9 shows a conceptual realization of the logic
used to implement the control of each intx# pin.
See also Section 3.6, “TM1300 to Host Interrupts.”
11.8
PCI BUS PROTOCOL OVERVIEW
TM1300’s PCI interface can generate and respond to
several types of PCI bus commands. Table 11-20 lists
the 12 possible commands and whether or not TM1300
can generate them.
Table 11-21 lists the 12 possible commands and wheth-
er or not TM1300 can respond to them.
The basic transfer mechanism on the PCI bus is a burst,
which consists of an address phase followed by one or
more data phases. In TM1300, the DSPCPU and ICP are
the only two units that can cause TM1300 to become a
PCI-bus initiator, i.e., only the DSPCPU and ICP can ac-
cess external resources.
11.8.1
Single-Data-Phase Operations
When the DSPCPU reads or writes PC memory, the PCI
transaction has only a single data phase. A typical sin-
gle-data-phase
read
operation
is
illustrated
in
Figure 11-10. During the first clock period, the TM1300
Table 11-19. INT_CTL Bits
INT_CTL
PCI Signal
Programming
Field
Bit
INT
0
inta#
0
Deassert intx#
1
Assert intx# (if enabled);
i.e., pull intx# pin to a low
logic level
1
intb#
2
intc#
3
intd#
IE
4
inta#
0
Disable open-collector
output to intx#
1
Enable open-collector
output to intx#
5
intb#
6
intc#
7
intd#
IS
8
inta#
Reads state of intx# pin:
0
No interrupt asserted
(intx# is high)
1
Interrupt is asserted
(intx# is low)
9
intb#
10
intc#
11
intd#
Table 11-20. TM1300 PCI Commands as Initiator
TM1300 Generates
TM1300 Cannot
Generate
Conguration read
Conguration write
Memory read
Memory read multiple
Memory write
Memory write and invalidate
I/O read
I/O write
Interrupt acknowledge
Special cycle
Dual address
Memory read line
Table 11-21. TM1300 PCI commands as target
TM1300 Responds To
TM1300 Ignores
Conguration read
Conguration write
Memory read
Memory write
Memory write and invalidate
Memory read line
Memory read multiple
I/O read
I/O write
Interrupt acknowledge
Special cycle
Dual address
INTx
oc
PCI intx#
IEx
ISx
Figure 11-9. Conceptual realization of intx# pin con-
trol logic.