IBM POWERPC 750GL User Manual
Page 312
User’s Manual
IBM PowerPC 750GX and 750GL RISC Microprocessor
Bus Interface Operation
Page 312 of 377
gx_08.fm.(1.2)
March 27, 2006
Figure 8-19 shows three ways to delay single-beat reads using data-delay controls:
• The TA signal can remain negated to insert wait states in clock cycles 3 and 4.
• For the second access, DBG could have been asserted in clock cycle 6.
• In the third access, DRTRY is asserted in clock cycle 11 to flush the previous data.
Note: All bidirectional signals are tristated between bus tenures. The pipelining shown in Figure 8-19 can
occur if the second access is not another load (for example, an instruction fetch).
Figure 8-19. Single-Beat Reads Showing Data-Delay Controls
BR
BG
ABB
TS
A[0–31]
TT[0–4]
TBST
GBL
AACK
ARTRY
DBG
DBB
D[0–63]
TA
DRTRY
TEA
CPU A
CPU A
CPU A
Read
Read
Read
In
In
Bad
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
In