PCI Bus Host Bridge
9-6
Élan™SC520 Microcontroller User’s Manual
Figure 9-5
PCI Bus Clocking Example 1: Lightly Loaded System
Figure 9-6
PCI Bus Clocking Example 2: Heavily Loaded System
9.3.1.1
Running the Élan™SC520 Microcontroller at 33.333 MHz
The clock that is supplied to the PCI bus (CLKPCIOUT) is exactly the same as the frequency
of the crystal. The ÉlanSC520 microcontroller simply buffers the 33-MHz crystal input and
provides it to the CLKPCIOUT pin. Because crystals have inaccuracies, it is possible that
these inaccuracies cause the period of CLKPCIOUT to become marginally less than 30 ns.
CLKPCIOUT
CLKPCIIN
PCI Device 0
CLK
Notes:
In this lightly loaded system, no clock buffering is required.
Élan™SC520 Microcontroller
CLKPCIOUT
CLKPCIIN
PCI Device 0
CLK
PCI Device 1
CLK
PCI Device 2
CLK
PCI Device 3
CLK
PCI Device 4
CLK
Notes:
In this heavily loaded system, clock buffering is required.
Élan™SC520 Microcontroller
Содержание Elan SC520
Страница 1: ...lan SC520 Microcontroller User s Manual Order 22004A...
Страница 4: ...iv lan SC520 Microcontroller User s Manual...
Страница 28: ...Introduction xxviii lan SC520 Microcontroller User s Manual...
Страница 42: ...Architectural Overview 1 14 lan SC520 Microcontroller User s Manual...
Страница 78: ...System Initialization 3 22 lan SC520 Microcontroller User s Manual...
Страница 108: ...Clock Generation and Control 5 10 lan SC520 Microcontroller User s Manual...
Страница 118: ...Reset Generation 6 10 lan SC520 Microcontroller User s Manual...
Страница 148: ...System Arbitration 8 24 lan SC520 Microcontroller User s Manual...
Страница 214: ...SDRAM Controller 10 36 lan SC520 Microcontroller User s Manual...
Страница 230: ...Write Buffer and Read Buffer 11 16 lan SC520 Microcontroller User s Manual...
Страница 288: ...GP Bus DMA Controller 14 22 lan SC520 Microcontroller User s Manual...
Страница 316: ...Programmable Interval Timer 16 8 lan SC520 Microcontroller User s Manual...
Страница 328: ...Software Timer 18 4 lan SC520 Microcontroller User s Manual...
Страница 346: ...Real Time Clock 20 12 lan SC520 Microcontroller User s Manual...
Страница 360: ...UART Serial Ports 21 14 lan SC520 Microcontroller User s Manual...
Страница 414: ...AMDebug Technology 26 8 lan SC520 Microcontroller User s Manual...