Chapter 8: PCI/G-Bus Bridge
TX7901 User’s Manual (Rev. 6.30T – Nov, 2001)
8-11
Figure 8-7 PCI Master Reading from G-Bus
8.2.5 Doorbell
Feature
The PGB G-Bus Command and Status register has an interrupt bit that may be set by a PCI
Master requiring attention from resources on the G-Bus.
8.2.6 PCI Transaction Commands Supported.
The PGB maps G-Bus transactions to any of the 16 possible PCI transactions using a
combination of the G-Bus gbsgRdB signal and a 3-bit field in the g2pCycleType register.
The PCI core supports a subset of the possible PCI transactions. Table 8-3 shows the
supported PCI transaction types in each direction.
Table 8-3 Supported PCI transaction types
C/BE#
Transaction Type
PCI to G-Bus
G-Bus to PCI
0000
Interrupt Acknowledge
No
Yes
0001
Special Cycle
No
Yes
0010
I/O Read
Yes
Yes
0011
I/O Write
Yes
Yes
0100
Reserved
No
Yes
0101
Reserved
No
Yes
0110
Memory Read
Yes
Yes
0111
Memory Write
Yes
Yes
1000
Reserved
No
Yes
Retry Logic
Wait State
Logic
PCI
G-Bus
Parity
Fatal
P
C
I
C
O
R
E
G-Bus
Handshake
Logic
Address
Generate and
Data un-
Folding to 32
bits for 32-bit
Slaves
Status Reg.
Fatal Error
Interrupt
Logic
Parity Error
Interrupt
Logic
Word Count
Summary of Contents for TMPR7901
Page 1: ...TX System RISC TX79 Family TMPR7901 Symmetric 2 way superscalar 64 bit CPU ...
Page 14: ...Handling Precautions ...
Page 15: ......
Page 17: ...1 Using Toshiba Semiconductors Safely 1 2 ...
Page 41: ...4 Precautions and Usage Considerations 4 2 ...
Page 42: ...TX7901 User s Manual Rev 6 30T November 2001 DOCUMENT NUMBER M 99 00004 07 ...
Page 43: ......
Page 259: ...Chapter 13 Removed TX7901 User s Manual Rev 6 30T Nov 2001 13 1 13 Removed ...
Page 260: ...Chapter 13 Removed TX7901 User s Manual Rev 6 30T Nov 2001 13 2 ...