
TM1100 Preliminary Data Book
Philips Semiconductors
21-8
PRELIMINARY INFORMATION
File: pci-xio.fm5, modified 7/26/99
the frequency limits given in the AC/DC timing character-
ization data for TM1100. Odd values of ‘Clock Frequen-
cy’ are recommended, resulting in an even divider, which
generates a 50% duty cycle PCI_CLK.
21.5.2
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.
21.6
PCI-XIO BUS TIMING
The timing for the PCI-XIO bus is shown below: Note that
the ‘fat’ lines indicate active drive by TM1100. Thin lines
indicate areas where the TM1100 is not actively driving
(in these areas, pull-up resistors retain the signal high for
control
signals,
PCI_AD
lines
are
left
floating).
timing for a DMA burst read transfer of 2 bytes, and
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
extended by the wait states. In the write case, the IO-
WR# enable and DS# are delayed by the wait states.
Table 21-3. PCI_CLK Frequencies for 133.0 MHz
TM1100 Highway Clock
Clock
Frequency
(use odd
values)
TM1100
Clocks
PCI-XIO Clock
Period, ns
Frequency,
MHz
0
illegal
1
2
15
66.5
2
3
22.5
44.33
3
4
30
33.25
...
30
31
233
4.29
31
32
241
4.16
Table 21-4. 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 21-10. 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