Intel manual Pin & Signal Descriptions for the PXA255 Processor Sheet 9

Models: PXA255

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System Architecture

Table 2-6. Pin & Signal Descriptions for the PXA255 Processor (Sheet 9 of 9)

Pin Name

Type

Signal Descriptions

Reset State

Sleep State

 

 

 

 

 

 

 

JTAG test data output. (output) Data from the PXA255

 

 

TDO

OCZ

processor is returned to the JTAG controller using this

Hi-Z

Hi-Z

 

 

pin.

 

 

 

 

 

 

 

 

 

JTAG test mode select. (input) Selects the test mode

 

 

TMS

IC

required from the JTAG controller. This pin has an

Input

Input

 

 

internal pull-up resistor.

 

 

 

 

 

 

 

TCK

IC

JTAG test clock. (input) Clock for all transfers on the

Input

Input

JTAG test interface.

 

 

 

 

 

 

 

 

 

TEST

IC

Test Mode. (input) Reserved. Must be grounded.

Input

Input

 

 

 

 

 

TESTCLK

IC

Test Clock. (input) Reserved. Must be grounded.

Input

Input

Power and Ground Pins

 

 

 

VCC

SUP

Positive supply for internal logic. Must be connected

Powered

Note [6]

to the low voltage supply on the PCB.

 

 

 

 

 

 

 

 

 

VSS

SUP

Ground supply for internal logic. Must be connected to

Grounded

Grounded

the common ground plane on the PCB.

 

 

 

 

 

 

 

 

 

PLL_VCC

SUP

Positive supply for PLLs and oscillators. Must be

Powered

Note [6]

connected to the common low voltage supply.

 

 

 

 

 

 

 

 

 

PLL_VSS

SUP

Ground supply for the PLL. Must be connected to

Grounded

Grounded

common ground plane on the PCB.

 

 

 

 

 

 

 

 

 

 

 

Positive supply for all CMOS I/O except memory bus

 

 

VCCQ

SUP

and PCMCIA pins. Must be connected to the common

Powered

Note [7]

 

 

3.3v supply on the PCB.

 

 

 

 

 

 

 

 

 

Ground supply for all CMOS I/O except memory bus

 

 

VSSQ

SUP

and PCMCIA pins. Must be connected to the common

Grounded

Grounded

 

 

ground plane on the PCB.

 

 

 

 

 

 

 

 

 

Positive supply for memory bus and PCMCIA pins.

 

 

VCCN

SUP

Must be connected to the common 3.3v or 2.5v supply on

Powered

Note [7]

 

 

the PCB.

 

 

 

 

 

 

 

 

 

Ground supply for memory bus and PCMCIA pins.

 

 

VSSN

SUP

Must be connected to the common ground plane on the

Grounded

Grounded

 

 

PCB.

 

 

 

 

 

 

 

Table 2-7. Pin Description Notes (Sheet 1 of 2)

Note

Description

 

 

 

GPIO Reset Operation: Configured as GPIO inputs by default after any reset. The input buffers for these pins

[1]

are disabled to prevent current drain and the pins are pulled high with 10K to 60K internal resistors. The input

paths must be enabled and the pullups turned off by clearing the Read Disable Hold (RDH) bit described in

 

Section 3.5.7, “Power Manager Sleep Status Register (PSSR)” on page 3-29. Even though sleep mode sets the

 

RDH bit, the pull-up resistors are not re-enabled by sleep mode.

 

 

[2]

Crystal oscillator pins: These pins are used to connect the external crystals to the on-chip oscillators. Refer to

Section 3.3.1, “32.768 kHz Oscillator” on page 3-4and Section 3.3.2, “3.6864 MHz Oscillator” on page 3-4for

 

details on Sleep Mode operation.

 

 

 

GPIO Sleep operation: During the transition into sleep mode, the state of these pins is determined by the

 

corresponding PGSRn. See Section 3.5.10, “Power Manager GPIO Sleep State Registers (PGSR0, PGSR1,

[3]

PGSR2)” and Section 4.1.3.2, “GPIO Pin Direction Registers (GPDR0, GPDR1, GPDR2)” on page 4-8. If

selected as an input, this pin does not drive during sleep. If selected as an output, the value contained in the

 

Sleep State Register is driven out onto the pin and held there while the PXA255 processor is in Sleep Mode.

 

GPIOs configured as inputs after exiting sleep mode cannot be used until PSSR[RDH] is cleared.

 

 

Intel® PXA255 Processor Developer’s Manual

2-17

Page 47
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Intel manual Pin & Signal Descriptions for the PXA255 Processor Sheet 9, Pin Description Notes Sheet 1