Terminations; Terminations: Pull-Up/Pull-Down - Intel 80331 Design Manual

Terminations

This chapter provides the recommended pull-up and pull-down terminations for a 80331 layout.
Table 3 lists these 80331 termination values. On a motherboard, the PCI Local Bus Specification,
Revision 2.3 requires that the PCI signals provide the termination resistors. Pull-ups on the PCI
signals are not required with PCIODT_EN = 1 (enabled), because they are implemented on the die.
Refer to the
Table 3. Terminations: Pull-up/Pull-down (Sheet 1 of 4)
Signal
PWRDELAY
TRST#
TMS
TDI
TCK
GPIO[0]/U0_RXD
GPIO[1]/U0_TXD
GPIO[2]/U0_CTS#
GPIO[3]/U0_RTS#
GPIO[4]/U1_RXD
GPIO[5]/U1_TXD
GPIO[6]/U1_CTS#
GPIO[7]/U1_RTS
ARB_EN
Table 3 for more information.
Pull-up or Pull-down
Resistor Value (in Ohms)
If battery backup is
implemented:
• 1.5 K pull-up to 3.3 V is
required on
PWRDELAY.
Battery Backup not
implemented:
• This pin can be
permanently pulled low
with a 1.5K pull-down
1.5K pull-down*
NC when not being used
(has internal pull-up)
NC when not being used
(has internal pull-up)
1.5K pull-down when not
used
8.2 K pull-up
8.2 K pull-up
8.2 K pull-up
8.2 K pull-up
8.2 K pull-up
8.2 K pull-up
8.2 K pull-up
8.2 K pull-up
(see comments)
Intel® 80331 I/O Processor Design Guide
NOTES:
• Alternatively tied to P_RST# refer to
Multi-ICE" on page 142 for more information about using with a
ICE.
• When not used this signal is be tied to GND.
• This pin has an internal pull-up.
Note: GPIO[7:0] initializes as inputs on assertion of P_RST#.
Note: GPIO[7:0] initializes as inputs on assertion of P_RST#.
Note: GPIO[7:0] initializes as inputs on assertion of P_RST#.
Note: GPIO[7:0] initializes as inputs on assertion of P_RST#.
Note: GPIO[7:0] initializes as inputs on assertion of P_RST#.
Note: GPIO[7:0] initializes as inputs on assertion of P_RST#.
Note: GPIO[7:0] initializes as inputs on assertion of P_RST#.
Note: GPIO[7:0] initializes as inputs on assertion of P_RST#.
This signal has been defeatured. Please refer to the Intel® 80331
Specification Update for more information.
Terminations
Comments
Section 11.4.2, "ARM
3
23