Functional Description

 

 

Table 2-1.

Signal Descriptions (Sheet 3 of 3)

 

 

 

 

 

Name

Type

Description

 

 

 

 

 

nRESET_OUT

OCZ

Reset out. This signal is asserted when nRESET is asserted and deasserts when

 

 

 

the processor has completed resetting. nRESET_OUT is also asserted for "soft"

 

 

 

reset events (sleep and watchdog).

 

 

 

 

 

nTRST

IC

Test interface reset. Note this pin has an internal pull-down resistor and must be

 

 

 

driven high to enable the JTAG circuitry. If left unconnected, this pin is pulled low

 

 

 

and disables JTAG operation.

 

 

 

 

 

TDI

IC

JTAG test interface data input. Note this pin has an internal pull-up resistor.

 

 

 

 

 

TDO

OCZ

JTAG test interface data output. Note this pin does not have an internal pull-up

 

 

 

resistor.

 

 

 

 

 

TMS

IC

JTAG test interface mode select. Note this pin has an internal pull-up resistor.

 

 

 

 

 

TCK

IC

JTAG test interface reference clock. This times all the transfers on the JTAG test

 

 

 

interface. Note this pin has an internal pull-down resistor.

 

 

 

 

 

TCK_BYP

IC

Test clock PLL bypass. When TCK_BYP is high, the TESTCLK is used as the

 

 

 

core clock in place of the PLL clock; when low, the internal PLL output is used.

 

 

 

This signal has no relation to the JTAG TCK pin.

 

 

 

 

 

TESTCLK

IC

Test clock. TESTCLK is used to provide the core clock when TCK_BYP is high. It

 

 

 

should be tied low if TCK_BYP is low. This pin should be used for test purposes

 

 

 

only. An end user should ground this pin.

 

 

 

 

 

VDD

Positive supply for the core. Nine pins are allocated to this supply; eight pins are

 

 

 

labeled VDD. The ninth pin, labeled VDDP is dedicated to the PLL supply and

 

 

 

should be tied directly to the VDD power plane with the other eight VDD pins.

 

 

 

 

 

VDDX

Positive supply for the pins. Twenty pins are allocated to VDDX, labeled VDDX1,

 

 

 

VDDX2 and VDDX3. All of these pins should be tied directly to the VDDX power

 

 

 

plane.

 

 

 

 

 

VSS

Ground supply. Nine pins are allocated to VSS, including one for the PLL.

 

 

 

 

 

VSSX

Ground supply for the I/O pins. Eighteen pins are allocated to VSSX.

 

 

 

 

2-6

SA-1100 Developer’s Manual

Page 34
Image 34
Intel SA-1100 manual Signal Descriptions Sheet 3, Tdo Ocz, Vdd, Vssx