8-4 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part III. The Hardware Interface

Figure 8-2. 60x-Compatible Bus Mode

8.3 60x Bus Protocol Overview

Typically, 60x bus accesses consist of address and data tenures, which in turn each consist

of three phasesÑarbitration, transfer, and termination, as shown in Figure 8-3 The

independence of the tenures is indicated by showing the data tenure overlap the next

address tenure), which allows split-bus transactions to be implemented at the system level

in multiprocessor systems. Figure 8-3 shows a data transfer that consists of a single-beat

transfer of as many as 256 bits. Four-beat burst transfers of 32-byte cache blocks require

data transfer termination signals for each beat of data. Note that the MPC8260 supports port

sizes of 8, 16, 32, and 64 bits and requires the additional bus signal, PSDVAL, which is not

BR
BG
TS
A[0Ð31]
TT[0Ð4]
TSIZ[0Ð3]
TBST
CI
WT
GBL
AACK
ARTRY
DBG
D[0Ð63]
DP[0Ð7]
TA
TEA
MPC8260
I/O
MEM
Data + Attributes
Address + Attributes
Memory Controller Signals
External Device
BR
BG
DBG
Latch
Latch &
DRAM MUX
Memory Control Signals
AP[0Ð3]
TS
APE