Philips Semiconductors

Product specification

SCN2652/SCN68652

Multi-protocol communications controller (MPCC)

1995 May 01

22

DMA/PROCESSOR INTERFACE

For non-DMA operation TxBE and RxDA are set to the processor which then loads or reads data characters as required.

DMA

CONTROLLER

WORD COUNT

ADDRESS PTR

R/W CONTROL

RDREQ

ADDRESS

R/W CONTROLS

SCN2652

ADDRESS AND

CONTROL

SCN2652

RxA

WRREQ

TO PROCESSOR

RxDA

DB15–DB00

TxBE

A2–A0

BYTE

R/W

CE

DBEN

RxC TxC RxSI TxSO

MODEM OR DCE

DATA BUS

SYSTEM ADDRESS AND CONTROL BUS

PROCESSOR (P)

AND

SUPPORT LOGIC:

DB15–DB00

ADDRESS, R/W,

CONTROL

RxE

RxSA

TxA

TxE

TxU

S/F

RESET

MM

RxDA

TxBE

1.

INITIALIZES

SCN2652

2.

SETS/RESETS

TSOM, TEOM

3.

RESPONDS

TO RxSA

8 OR 16 BITS

R/W

MEMORY

DATA BUS

ADDRESS,

CE, R/W

SD00074

Figure 19. Typical Applications (cont.)

CHANNEL INTERFACE

COMPUTER

OR

TERMINAL

LR

MPCC

SCN2652

TxC

BAUD

RATE

GENERATOR

RxC

LD

LD

LR

LR

LD

LD

LR

TxSO

RxSI

MPCC

SCN2652

TxC

BAUD

RATE

GENERATOR

RxC

TxSO

RxSI

COMPUTER

OR

TERMINAL

No Modem – DC Baseband Transmission

SD00075

Figure 20. Typical Applications (cont.)