Reset Generation
Élan™SC520 Microcontroller User’s Manual
6-5
CPU reset, see the
Am486
®
DX/DX2 Microprocessor Hardware Reference Manual, 1994
(order #17965).
Note: The CFG3–CFG0 and RSTLD7–RSTLD0 pins are latched only as a result of the
assertion of the PWRGOOD signal, and not as a result of the SYS_RST bit, AMDebug
system reset event, or watchdog timer event.
If the ICE_ON_RST bit in the Reset Configuration (RESCFG) register is set to a 1, the
AMDebug utility enters into AMDebug mode after system reset.
The states of the ÉlanSC520 microcontroller cores after system reset are shown in
Table 6-4. See the “Initialization” section at the end of each chapter for more detailed
information.
Table 6-4
States of Cores after System Reset
Core
State
Comment
Am5
x
86 CPU
Enabled
CPU clock frequency is set to 100 MHz. Internal
registers and internal cache are reset.
System arbiter
Enabled
Default is nonconcurrent arbitration mode. All bus
masters are disabled except the CPU as PCI and
internal Am5
x
86 CPU bus master.
PCI host bridge master controller
Enabled
PCI host bridge target controller
Disabled
SDRAM controller
Disabled
No banks are enabled.
Write buffer and read buffer
Disabled
ROM controller
Enabled
BOOTCS (only) is enabled at system reset
GP bus controller
Enabled
External GP bus is disabled until PAR registers are
initialized.
GP-DMA controller
Enabled
All channels are masked off.
Programmable interrupt controller
(PIC)
Enabled
Interrupts are masked at the CPU. NMIs are
disabled.
Software timer
Enabled
General-purpose (GP) timers
Disabled
All GP timer registers are reset to 0. Each timer must
be programmed before it can be used.
Programmable interval timer (PIT)
Disabled
Each PIT channel must be programmed before it
can be used.
Watchdog timer (WDT)
Disabled
Real-time clock (RTC)
Enabled
UARTs
Disabled
Synchronous serial interface (SSI)
Disabled
Inactive until an SSI command is written.
Programmable input/output (PIO)
pins
Enabled
All PIO pins default to inputs and to their PIO
function.
JTAG test access port (TAP)
Enabled
JTAG_TRST should be asserted active Low to
ensure normal operation.
AMDebug mode
Enabled
If the ICE_ON_RST bit in the Reset Configuration
(RESCFG) register is set.
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...