Hardware Description
ARM DUI 0224I Copyright © 2003-2010 ARM Limited. All rights reserved. 3-39
3.5.1 ARM926EJ-S PXP Development Chip clocks
This section describes the clocks used by the ARM926EJ-S PXP Development Chip.
Figure 3-18 shows the clock circuitry inside the chip.
Figure 3-18 ARM926EJ-S PXP Development Chip internal multiplexors
HCLK
divider
CFGHCLKEXTDIVSEL[2:0]
HCLK
CFGHCLKDIVSEL[1:0]
ARM926EJ-S Dev. Chip
CFGDATA values
PLL
HCLKM1
HCLKM2
HCLKS
PLLCLKEXT
XTALCLKEXT
REFCLK32K
SDRAM
HDATAM1
HDATAM2
CFGAHBM1ASYNC
CFGAHBM2ASYNC
CFGAHBSASYNC
0
1
CFGUSEPLL
CFGPLLBYPASS
ARM
926EJ-S
System controller
CFGMBXCLKDIVSEL[1:0]
MBX
clock
divider
SMC clock
divider
Flash
CFGSMCCLKDIVSEL[1:0]
0
1
0
1
AHB
M1
bridge
AHB
M2
bridge
AHB
S
bridge
HCLKEXT
divider
HCLKEXT
CPUCLK
0
1
0
1
MPMC
PLLCLKEXT (OSC2)
On-chip
peripherals
MBX
GLOBALCLK (OSC0)
Low-power
mode logic
REFCLK32KDRVF2S
(from 32KHz osc.)
Configuration signals
(from SYS_CFGDATAx regs)
Asynchronous mode
bus clocks
(from clock
multiplexor logic)
Peripheral
clocks
CLCDC
CLCDCLKEXT (OSC4)
UARTCLKEXT
SCIREFCLKEXT
TIMCLKEXT
SSPCLKEXT
Alternative
peripheral
clocks
SSMC
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