MK50H25N ST Microelectronics, Inc., MK50H25N Datasheet - Page 6

• Manufacturer Part Number: MK50H25N
• Description: High Speed Link Level Controller
• Manufacturer: ST Microelectronics, Inc.

MK50H25
Table 1: PIN DESCRIPTION (continued)
SECTION 3
OPERATIONAL DESCRIPTION
The STMicroelectronics MK50H25 Multi-Logical
Link Communications Controller device is a VLSI
product intended for high performance data com-
munication applications requiring X.25 link level
control. The MK50H25 will perform all frame for-
matting, such as: frame delimiting with flags, FCS
(CRC) generation and detection, and zero bit in-
sertion and deletion for transparency. The
MK50H25 also handles all supervisory (S) and
unnumbered (U) frames (see Tables A & B). The
MK50H25 also includes a buffer management
mechanism that allows the user to transmit and/or
receive multiple frames for each active channel
or DLCI. Contained in the buffer management is
an on-chip dual channel DMA: one channel for re-
ceive and one channel for transmit.
6/62
SIGNAL NAME
VSS-GND
A<23:16>
SYSCLK
RESET
RCLK
TCLK
DTR
DSR
VCC
RTS
CTS
RD
TD
[37-43]
PIN(S)
32-39
[1,26]
1,24
[25]
[28]
[29]
[30]
[31]
[32]
[33]
[34]
[52]
23
25
26
27
28
29
30
31
48
TYPE
o/3s
IO
IO
O
I
I
I
I
I
As a Bus Slave, the MK50H25 asserts READY when it has put data on the
DAL lines during a READ cycle or is about to take data from the DAL lines
during a WRITE cycle. READY is a response to DAS and it will be released
after DAS or CS is negated.
RESET is the Bus signal that will cause MK50H25 to cease operation, clear
its internal logic and enter an idle state with the Power Off bit of CSR0 set.
TRANSMIT CLOCK. A 1x clock input for transmitter timing. TD changes on
the falling edge of TCLK. The frequency of TCLK may not be greater than
the frequency of SYSCL
DATA TERMINAL READY, REQUEST TO SEND. Modem control pin. Pin
26 is configurable through CSR5. This pin can be programmed to behave as
output RTS or as programmable IO pin DTR. If configured as RTS, the
MK50H25 will assert this pin if it has data to send and throughout the
transmission of a signal unit.
RECEIVE CLOCK. A 1x clock input for receiver timing. RD is sampled on
the rising edge of RCLK. The frequency of RCLK may not be greater than
the frequency of SYSCLK.
SYSTEM CLOCK. System clock used for internal timing of the MK50H25.
SYSCLK should be a square wave, of frequency up to 33 MHz.
TRANSMIT DATA. Transmit serial data output.
DATA SET READY, CLEAR TO SEND. Modem Control Pin. Pin 30 is
configurable through CSR5. This pin can be programmed to behave as input
CTS or as programmable IO pin DSR. If configured as CTS, the MK50H25
will transmit all ones while CTS is high.
RECEIVE DATA. Received serial data input.
Address bits <23:16> used in conjunction with DAL<15:00> to produce a 24
bit address. MK50H25 drives these lines only as a Bus Master. A23-A20
may be driven continuously as described in the CSR4<7> BAE bit.
Ground Pins
Power Supply Pin
+5.0 VDC + 5%
The MK50H25 can be used with any popular 16
or 8 bit microprocessor. A possible system con-
figuration for the MK50H25 is shown in Figure 1.
This document assumes that the processor has a
byte addressable memory organization.
The MK50H25 will move multiple blocks of re-
ceive and transmit data directly in and out of
memory through the Host’s bus.
The MK50H25 may be operated in full or half du-
plex mode. In half duplex mode the RTS and
CTS modem control pins are provided. In full du-
plex mode, these pins become user programma-
ble I/O pins.
All signal pins on the MK50H25 are TTL compat-
ible.
MK50H25 independent of the physical interface.
As shown in Fig. 1, line drivers and receivers are
used for electrical connection to the physical
layer.
This has the advantage of making the
DESCRIPTION