MCD221

2–3

MOTOROLA

PIN DESCRIPTIONS

SIGNAL DESCRIPTIONS

Host Interface

Mnemonic

Type

Name and Function

A[13

… 1]

O

System Address Bus. The address must be stable before CS is asserted.

Active HIGH.

D[15

… 0]

B

System Data Bus. The data lines must be stable when CS is active during

a write and before DTACK is asserted during a read. Tri–state.

CS

I

Chip Select. Used to access the CIAP internal registers and buffers.

Active LOW.

R/W

I

Read/Write. Indicates the direction of the data transfer. When LOW, the

transfer is to the CIAP.

DTACK

B

Data Transfer Acknowledge. Active LOW. During normal host access,

DTACK is an output indicating that data has been put on (read cycles) or

read from (write cycles) the data bus. (Active pullup.) During DMA,

DTACK is an input indicating that the memory has put data on the data

bus.

INT

O

Interrupt. Released when the interrupt status register is read. Active

LOW.

IACK

I

Interrupt Acknowledge. Active LOW.

REQ

O

DMA Request. Active LOW.

ACK

I

Acknowledge. DMA handshake signal indicating that the bus is available

for data transfer. Active LOW.

RDY

O

Ready. DMA handshake signal indicating that the CIAP has completed

the data transfer. Tri–state. Active LOW. When released by the CIAP, the

output is forced high for a few nanoseconds before it is made tri–state.

DONE

I

Done. Indicates the last transfer of a DMA burst. Active LOW.

Serial Interface

Mnemonic

Type

Name and Function

SCLK

I

Serial Clock.

MOSI

I

Serial Data. Master out, slave in.

MISO

O

Serial Data. Master in, slave out.

MODE_0,

MODE_1

I

Serial Interface MODE bits.

00 = Write selected register

01 = Read selected register

10 = Write address

11 = No action

Data Input

Mnemonic

Type

Name and Function

CLI

I

Serial Bit Clock Input.

WSI

I

Word Clock Input.

DAI

I

Serial Data Input.

EFI

I

Error Flag Input.

SUBCODE/EBU

I

Subcode (P

… W) serial data input or EBU input for both main channel

and subchannel.

External Audio Interface

Mnemonic

Type

Name and Function

XCLI

I

External Audio Serial Bit Clock Input. When not used, the pin must be

connected to VCC or VSS.

XWSI

I

External Audio Word Clock Input. When not used, the pin must be

connected to VCC or VSS.

XDAI

I

External Audio Data Input. When not used, the pin must be connected to

VCC or VSS.