External Bus Interface
MPC885 PowerQUICC Family Reference Manual, Rev. 2
Freescale Semiconductor
13-15
During the data phase of a burst read cycle, the master receives data from the addressed slave. If the master
needs more than one data, it asserts BDIP. When the master receives the next-to-last data, it negates BDIP.
Thus, the slave stops driving new data after receiving the negation of BDIP at the rising clock edge.
In the case of 32-bit port size, the burst includes 4 beats. When the port size is 16 bits and controlled by
the internal memory controller, the burst includes 8 beats. When the port size is 8 bits and controlled by
the internal memory controller, the burst includes 16 beats. The MPC885 bus supports critical data first
access for fixed-size burst. The order of wraparound wraps back to the critical data. For example, assuming
data 2 is critical:
•
Case burst of four:
data 2
→
data 3
→
data 0
→
data 1
•
Case burst of eight:
data 2
→
data 3
→
data 4
→
.........
→
data 7
→
data 0
→
data 1
The following flow,
Figure 13-11
, and timing diagrams,
Figure 13-12
through
Figure 13-15
, show the
handshakes for burst read transactions.
Summary of Contents for PowerQUICC MPC870
Page 98: ...MPC885 PowerQUICC Family Reference Manual Rev 2 I 4 Freescale Semiconductor ...
Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Page 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Page 1336: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 16 Freescale Semiconductor ...
Page 1358: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 38 Freescale Semiconductor ...
Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...