Intel 855GME User Manual

80
Intel
®
855GME Chipset and Intel
®
6300ESB ICH Embedded Platform Design Guide
2. Reference these signals to ground planes and avoid routing across power plane splits.
3. The number of routing layer transitions should be minimized. When layout constraints require
a routing layer transition, any such transition shall be accompanied with ground stitching vias
placed within 100 mils of the signal via with at least one ground via for every two signals
making a layer transition.
DBR# should be routed to the system reset logic (e.g., the SYSRST# signal of the 6300ESB) and
initiate the equivalent of a front panel reset commonly found in desktop systems. The 150
Ω to
240
Ω pull-up resistor should be placed within 1 ns of the ITP700FLEX connector.
Note: The CPU should not be power cycled when DBR# is asserted.
DBA# is an optional system signal that may be used to indicate to the system that the ITP/TAP port
is being used. When not implemented, this signal may be left as no connect. When implemented, it
shall be routed with a 150
Ω to 240 Ω pull-up resistor placed within 1 ns of the ITP700FLEX
connector. Refer to the ITP700 Debug Port Design Guide for more details on DBA# usage.
The ITP700FLEX VTT and VTAP pins should be shorted together and connected to the VCCP
(1.05 V) plane with a 0.1 µF decoupling capacitor placed within 0.1 inch of the VTT pins. Table 19
summarizes termination resistors values, placement, and voltages the ITP signals need to connect
to for proper operation for onboard ITP700FLEX debug port.
Table 19. Recommended ITP700FLEX Signal Terminations (Sheet 1 of 2)
Signal Termination Value Termination Voltage Termination/Decap Location Notes
TDI 150 Ω ± 5% VCCP (1.05 V)
Within ± 300 ps of the Intel
Pentium M/Celeron M processor
CPU TDI pin
5
TMS 39.2
Ω ± 1% VCCP (1.05 V)
Within ± 200 ps of the
ITP700FLEX connector TMS pin
5
TRST# 510-680
Ω ±5% GND
Anywhere between Intel Pentium
M/Celeron M processor CPU and
ITP700FLEX connector
5
TCK 27.4
Ω ±1% GND
Within ± 200 ps of the ITP700
FLEX connector TCK pin
5
TDO
54.9
Ω ± 1% pull-up and
22.6
Ω ±1% series
resistor
VCCP (1.05 V)
Within 1” of the ITP700FLEX
connector TDO pin
1, 5
BCLK(p/n) 2
FBO
Connect to TCK pin of
Intel Pentium M/Celeron
M processor CPU
N/A N/A 1
RESET#
220
Ω ± 5% pull-up and
22.6
Ω ±1% series
resistor
VCCP (1.05 V)
Within 0.5” of the ITP700FLEX
connector RESET# pin
1
BPM[5:0]# Not Required 3
DBA# 150-240
Ω ±5%
VCC of target system
recovery circuit
Within 1 ns of the ITP700FLEX
connector DBA# pin
4
DBR# 150-240
Ω ±5%
VCC of target system
recovery circuit
Within 1 ns of the ITP700FLEX
connector DBR# pin

Intel 855GME Specifications

General

Brand	Intel
Model	855GME
Category	Computer Hardware
Language	English