
TM1300 Data Book
Philips Semiconductors
22-8
PRODUCT SPECIFICATION
A table of PCI-XIO Bus Clock frequencies versus Clock
field values is shown in Table 22-3. Note that the
PCI_CLK operating frequency should be set to observe
the frequency limits given in the AC/DC timing character-
ization data for TM1300. Odd values of ‘Clock Frequen-
cy’ are recommended, resulting in an even divider, which
generates a 50% duty cycle PCI_CLK.
22.5.2
Wait State Generator
The XIO Bus controller has an automatic wait state gen-
erator to allow for read and write cycle times of devices
on the XIO bus.
22.6
PCI-XIO BUS TIMING
The timing for the PCI-XIO bus is shown below: Note that
the ‘fat’ lines indicate active drive by TM1300. Thin lines
indicate areas where the TM1300 is not actively driving.
(In these areas, pull-up resistors retain the signal high for
control
signals,
PCI_AD
lines
are
left
floating.)
Figure 22-10 shows the timing for a single byte read
transfer. Figure 22-11 shows the timing for a single byte
read transfer with wait states. Figure 22-14 shows the
timing for a DMA burst read transfer of 2 bytes, and
Figure 22-16 shows the timing for a DMA burst write
transfer of 2 bytes. The DMA burst transfers are shown
at maximum rate, with zero wait states. DMA burst trans-
fers with wait states insert wait states between the trans-
fers. In the read case, the IORD# enable and DS# are ex-
tended by the wait states. In the write case, the IOWR#
enable and DS# are delayed by the wait states.
Table 22-4. Wait state generator codes
Code
Wait States
00
11
22
...
77
PCI_CLK
PCI_FRAME#
PCI_IRDY#
PCI_TRDY#
PCI_DEVSEL#
Frame Time
Bus Turnaround
XIO Transfer
Figure 22-10. PCI-XIO Bus timing: single byte read, 0 wait states
& Address Setup
PCI_AD[23:0]: ADDR
XIO Addrs
PCI Address
PCI_AD[31:24]: DATA
Read Data
PCI Address
PCI_INTB#/CE#
PCI_C/BE2#/DS#
PCI Command
PCI_C/BE1#/IOWR#
PCI Command
PCI_C/BE0#/IORD#
PCI Command
Read Sample Point
Bus Idle