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AMD Geode™ LX Processors Data Book 533
GeodeLink™ Control Processor
33234H
6.13 GeodeLink™ Control Processor
The GeodeLink Control Processor (GLCP) functionality
covers these areas (see Figure 6-55):
• Scan chain control
• JTAG interface to boundary scan, BIST, GLIU1, and
debug logic
• Power (clock) control
• Reset logic
• PLL control
• Internal logic analyzer/debugger
• 1KB FIFO/SRAM
• Compliant with GLIU System Architecture Specification
v1.07
• Supports AMD Geode™ CS5536 companion device
interface
• Supports physical pins for SUSPA# and IRQ13
• Supports muxed pin for SUSP#
6.13.1 TAP Controller
The TAP controller is IEEE 1149.1 compliant. TMS, TDI,
TCLK, and TDO are directly supported (TRST is available
as a bootstrap pin during reset, but is always inactive if the
system reset is inactive). The Instruction register (IR) is 25
bits wide. The meanings of the various instructions are
shown in Table 6-81 on page 534 along with the length of
the Data register that can be accessed once the instruction
is entered. All Data registers shift in and out data, LSB first.
The Instruction and all Data registers are shift registers, so
if more bits are shifted in than the register can hold, only
the last bits shifted in (the MSBs) are used.
The TAP controller has specific pre-assigned meanings to
the bits in the 25-bit IR. The meanings are summarized in
Table 6-82 on page 534. Note that the bits only affect the
chip once the “Update-IR” JTAG state occurs in the JTAG
controller. Shifting through these bits does not change the
state of internal signals (for example TEST_MODE). For
details on JTAG controller states, refer to the IEEE Stan-
dard 1149.1-1990.
Figure 6-55. GLCP Block Diagram
Debug
Debug
Action
Decode
GLIU Interface
Debug
Control
Diagnostic Bus
Scan, BIST, Clock, Reset, Suspend Signals
TCLK
TMS
TDI
TDO
rqin, rqout, dain, daout
Off-Chip
Diagnostic Pins
GLIU Clock Frequency
Debug Clock Frequency (varies)
TCLK Clock Frequency
Data and Control Buses
Control Only
Event
Generator
IEEE 1149.1
Interface
Comparators
Clock, Reset,
ACPI Control
Scan and BIST
Control
Serial-to-GLIU
Conversion
128 WORD
64-Bit
FIFO
TDBGI, TDBGO
IRQ13
INTA#
SUSP#
SUSPA#
GIO_IGNNE
VA_FERR
GIO_NMI
GIO_INIT
GIO_INTR
PCI Clock Frequency
GIO
Synchronizing
AMD Geode™
Companion
Device
Interface
(GIO)