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CL-PS7111

Low-Power System-on-a-Chip

Cirrus Logic 

CL-PS7111

Low-Power System-on-a-Chip

2.2 Pin Descriptions

2.2.1

External Signal Functions

Function

Address and

Data Bus

Memory and

Expansion

Interface

Interrupts

Power

Management

Signal

Name

Type Description

D[0–31]

I/O 32-bit system data bus for DRAM, ROM, and memory-mapped expansion.

A[0–14]

O Least-significant 15 bits of system byte address during ROM and expansion cycles.

A[15]/

13-bit multiplexed DRAM word address during DRAM cycles or address bits 16 to 27

DRA[12]–

O of system byte address during ROM and expansion cycles.

A[27]/DRA[0]

NRAS[0–1] O DRAM RAS outputs to DRAM banks 0–1.

NCAS[0–3] O DRAM CAS outputs for bytes 0 to 3 within 32-bit word. NCAS[0] enables D[7:0].

NMOE

O DRAM, ROM, and expansion output enable.

NMWE

O DRAM, ROM, and expansion write enable.

NCS[0–3]

O Expansion channel I/O strobes. Active-low, SRAM-like chip selects for expansion.

NCS[4–5]

O

Expansion channel I/O strobes. Active-low chip select for expansion of low for

CL-PS6700 interface.

EXPRDY

I Expansion channel ready. Extends bus cycle when low.

WRITE

O

Transfer direction. Low during reads, high during writes from the CL-PS7111. Also

connected to PTYPE of CL-PS6700.

WORD

O

Word access enable. Driven high during word-wide cycles; low during byte-wide

cycles.

EXPCLK

I/O

Expansion clock output. Clock output at the same phase and speed as the CPU

clock. In 13-MHz mode, this pin is used as the clock input.

MEDCHG/

NBROM

I

Media changed input. Active-high deglitched input for media insertion; should be set

low during NPOR to enable boot code.

NEXTFIQ

I External active-low fast interrupt request input.

EINT[3]

I External active-high interrupt request input.

NEINT[1–2] I Two general-purpose, active-low interrupt inputs.

NPWRFL

I Power fail input. Active-low deglitched input to force system into the standby state.

BATOK

I

Main battery OK input. Falling edge generates a FIQ; a low level in standby mode

inhibits system start up; deglitched input.

NEXTPWR

I

External power sense. Must be driven low if the system is powered by external

source.

NBATCHG

I

New battery sense. Must be driven low if battery voltage falls below the ‘no-battery’

threshold.

September 1997

PRELIMINARY DATA BOOK v2.0

9

PIN INFORMATION

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