MK50H25PLCC datasheet(2/64 Pages) STMICROELECTRONICS

2 / 64 page

For added flexibility a transparent mode provides

an HDLC transport mechanism without link layer

support. This flexible transparent mode may be

easily entered and exited without affecting the

X.25 link status or the link state variables kept by

the MK50H25. In this mode no protocol process-

ing is done and it is up to the user to take care of

the upper level software. Single or extended Ad-

dress field filtering and Control field handling are

optionally supported within the transparent mode.

One of the outstanding features of the MK50H25

is its buffer management which includes on-chip

dual channel DMA. This feature allows users to

receive and transmit multiple data frames at a

time. (A conventional serial communications con-

trol chip plus a separate DMA chip would handle

data for only a single block at a time.)

The

MK50H25 will move multiple blocks of receive

and transmit data directly into and out of memory

through the Host’s bus. A possible system con-

figuration for the MK50H25 is shown in figure 1.

The MK50H25 may be used with any of several

popular 16 and 8 bit microprocessors, such as

68020, 68000, 6800, Z8000, Z80, 8086, 8088,

80186, 80286, 80386SX, etc.

The MK50H25 may be operated in either full or

half duplex mode. In half duplex mode, the RTS

and CTS modem control pins are provided. In full

duplex mode, these pins become user program-

mable I/O pins. All signal pins on the MK50H25

are TTL compatible. This has the advantage of

making the MK50H25 independent of the physical

interface. As shown in figure 1, line drivers and

receivers are used for electrical connection to the

physical layer.

DESCRIPTION (Continued)

VSS-GND

DAL07

DAL06

DAL05

DAL04

DAL03

DAL02

DAL01

DAL00

READ

INTR

DALI

DALO

DAS

BMO, BYTE , BUSRE L

BMI, BUSAKO

HOLD, BUSRQ

ALE, AS

ADR

READY

RESE T

VSS-GND

HLDA

TCLK

A18

A19

A20

A21

A22

A23

DSR, CTS

SYSC LK

RCLK

DTR, RTS

VCC (+5V)

DAL08

DAL09

DAL10

DAL11

DAL12

DAL13

DAL14

DAL15

A16

A17

DIP48 PIN CONNECTION (Top view)

MK50H25

2/64

MK50H25PLCC Arkusz danych(PDF) 2 Page - STMicroelectronics

MK50H25PLCC Arkusz danych(HTML) 2 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

Arkusz danych Pobierz

Link URL