Clocks and Power Control
MPC885 PowerQUICC Family Reference Manual, Rev. 2
Freescale Semiconductor
14-11
Figure 14-6. Divided System Clocks (GCLK
x
) Timing Diagram
14.3.1.2
Memory Controller and External Bus Clocks
(GCLK1_50, GCLK2_50, CLKOUT)
The MPC885 provides the capability to run the external bus and memory controller at a lower frequency
than the internal modules. This capability is provided by the external bus frequency dividers. The external
bus clocks GCLK1_50 and GCLK2_50 are derived from GCLK1 and GCLK2, as determined by the
SCCR[EBDF]. SCCR[EBDF] is cleared by HRESET, and thus GCLK1_50 and GCLK2_50 default to
GCLK1 and GCLK2. The timing relationship between GCLKx and GCLKx_50 is shown in
Figure 14-7
.
Figure 14-7. Memory Controller and External Bus Clocks Timing
Diagram for EBDF=0 and EBDF=1
GCLK1 Divided by 1
GCLK2 Divided by 1
GCLK1 Divided by 2
GCLK2 Divided by 2
GCLK1 Divided by 4
GCLK2 Divided by 4
GCLK1
GCLK2
GCLK1_50
GCLK2_50
CLKOUT
GCLK1_50
GCLK2_50
(EBDF=00)
(EBDF=00)
(EBDF=01)
(EBDF=01)
CLKOUT
(EBDF=00)
(EBDF=01)
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 ...