ALDC1-5S-L 参数 Datasheet PDF下载

Product Part Number: IBM22-ALDC1005S

Document Number: DCALD5DSU-04

ALDC1-5S

Data Compression

I B M Microelectronics

2. ALDC1-5S enables the original data inter-

face to receive data and enables the com-

pressed data interface to send data.

3. ALDC1-5S receives, compresses, and sends

data until the original data interface transfer

count (TCO) equals the transfer size (XFR).

4. The original data interface signals end of

data to the encoder.

5. The encoder adds an end marker to the

compressed data stream.

6. When the compressed data interface sends

the end marker, ALDC1-5S asserts the

-UPIRQ

output and sets the Done (STAT(0))

bit to one.

If an error occurs during the compression oper-

ation then the

-UPIRQ

output is immediately

asserted, the Any Error (STAT(1)) bit is set to

one, the proper bit in the Error Status (ERRS)

register is also set to one, and the transfer is

cancelled.

pressed data to the external direct memory

access device.

The following sequence occurs:

1. ALDC1-5S clears the history buffer, resets

the transfer count registers (TCO and TCC)

to X

'

0000

'

, resets the Error Status (ERRS)

register to X

'

00

'

, and sets the Status

(STAT) register to X

'

80

'

(ie. Busy).

2. ALDC1-5S enables the compressed data

interface to receive data and enables the

original data interface to send data.

3. ALDC1-5S receives, decompresses, and

sends data until the compressed data inter-

face transfer count (TCC) equals the

transfer size (XFR).

4. The compressed data interface signals end

of data to the decoder.

5. The decoder strips off the end marker

which the encoder added.

6. When the original data interface sends the

last decompressed byte, the

-UPIRQ

output

is asserted and the Done (STAT(0)) bit is

set to one.

If an error occurs during the decompression

operation then the

-UPIRQ

output is immediately

asserted, the Any Error (STAT(1)) bit is set to

one, the proper bit in the Error Status (ERRS)

register is also set to one, and the transfer is

cancelled.

2.2.2 Decompression

The compressed data interface receives com-

pressed data from the external direct memory

access controller and sends it to the ALDC

decoder. The ALDC decoder decompresses the

data and sends it to the original data interface.

The original data interface sends the decom-

(C) IBM CORP. 1993, 1994. ALL RIGHTS RESERVED. USE IS FURTHER SUBJECT TO THE PROVISIONS ON THE BACK OF THE TITLE PAGE.

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