5-36
PCI Interface
5.9.3.26 PCI Arbiter Control
Address offset: 47-44h
Width:
32
Reset Value:
00000000h
Access:
Read/Write
The CPC700 PCI arbiter provides arbitration for up to 6 devices at PCI speeds up to 33Mhz. It is enabled/
disabled based on the boot strapping of the CPC700 TT[4] signal. See Section 6.4 “Power on Reset Pin
Strapping Options” for more information.
The CPC700 PCI arbiter provides a single, fixed, balanced tree priority scheme as shown in Figure 42.
Input 0 of each individual block has priority over input 1 of the block. This means request 0 has the highest
priority while request 5 has the lowest. Bus parking modes and max transfer counts per grant can be pro-
grammed via the PCI Arbiter Control register.
Figure 42.Arbiter Priority Resolution
.
Table 53.PCI Arbiter Control Register Bits
Bit(s)
Name
Description
26:0
Reserved
These bits are reserved and return 0 when read.
27
Bus Parking Mode
This bit controls the algorithm to use for determining the master on
which to park. 0=park on the CPC700, 1=park on last master.
31:28
Max Transfer Count
Per Grant
These bits controls the maximum number of consecutive transac-
tions a master can perform while a pending lower priority request
exists.
0
1
A0
0
1
0
1
A1
A2
B0
B1
C0
0
1
2
3
4
5
Balanced Tree
0
1
0
1
Request
Grant
Summary of Contents for CPC700
Page 10: ...Table of Contents x Table of Contents...
Page 16: ...Tables xvi List of Tables...
Page 28: ...1 12 CPC700 User s Manual Preliminary...
Page 72: ...3 36 Processor Interface...
Page 132: ...4 60 Memory Controller...
Page 184: ...5 52 PCI Interface...
Page 194: ...6 10 Clock Power Management and Reset...
Page 224: ...8 18 IIC...
Page 244: ...10 10 Interrupt Controller...
Page 246: ...I 11 2 JTAG...
Page 250: ...12 4 Processor Local Bus PLB...
Page 262: ...14 10 Register Summary...
Page 267: ...CPC700 User s Manual Preliminary...