
TM1300 Data Book
Philips Semiconductors
22-2
PRODUCT SPECIFICATION
The XIO Bus does not generate parity during XIO Bus
write transfers or check parity during XIO Bus read trans-
fers. This allows the XIO Bus to interface to standard 8-
bit devices without having to add parity-generation and
check logic. While the XIO Bus is active, the XIO Bus log-
ic inhibits parity checking and drives the PCI Parity and
Parity Error pins so that they do not float.
Word transfer is used to transfer the bytes to and from
the PCI bus for hardware simplicity. The primary intend-
ed use of the PCI-XIO Bus is for slow devices, ROMs,
flash EPROMs and I/O. Because the PCI-XIO bus is so
much slower than the TM1300, there is time available for
the TM1300 to pack and unpack the words. In the case
of ROMs and flash EPROMs, the data is typically com-
pressed, requiring the TM1300 CPU to both unpack and
decompress the data.
The PCI-XIO Bus Controller logic reconfigures the byte
enables as control signals for the attached XIO Bus chips
during XIO Bus transfers. It also drives the PCI_TRDY#
signal to the PCI Bus for each transfer. The PCI Bus byte
enables are reconfigured to generate XIO Bus timing sig-
nals: Read (IORD), Write (IOWR) and Data Strobe (DS).
These signals allow ROM, flash EPROM, 68K and x86
devices to be gluelessly interfaced to the XIO Bus. For a
single device, the PCI_INTB# line is used as the global
chip enable. If more than one device is to be added, an
external decoder, such as a 74FCT138, can be used to
decode the upper bits of the 24-bit transfer address, with
Audio In
Audio Out
DSPCPU
400 MIPS
2.5 GOPS
I$
D$
I2C Interface
Image
Co Processor
TM1300
MMI
PCI and External I/O (PCI-XIO) Bus Interface
VLD Assist
Video Out
Digital
DMSD
or Raw
Video
Serial
Digital
Audio
JTAG
XIO Bus
PCI - XIO Bus AD[31:0]
SDRAM: 32-bit data
SDRAM
Highway
Synchronous
Video In
Glueless
Flash
EPROM I/F
XIO
I/O Device
PCI
I/O Device
Clock
Camera
I2C Bus
CCIR 601
Digital
Video Out
V.34 Modem
Controls
PCI Bus
Controls
Serial I/F
Figure 22-1. Partial TM1300 chip block diagram