mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 716

• Manufacturer Part Number: mpc823rg
• Description: Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
• Manufacturer: Freescale Semiconductor, Inc

Communication Processor Module
16.9.18.3 CONNECTING TO APPLETALK. The MPC823 connects to LocalTalk and,
using the TXDx, RTSx, and RXDx pins, is an interface for the RS-422 transceiver. The
RS-422, in turn, is an interface for the LocalTalk connector. Although it is not shown, a
passive RC circuit is recommended between the transceiver and connector. Figure 16-88
illustrates how to connect the MPC823 to LocalTalk.
The 16x multiplier of a 3.686MHz clock can be generated from an external frequency source
or from one of the baud rate generators if the resulting output frequency is close to a multiple
of the 3.686MHz frequency. The MPC823 asserts the RTSx signal throughout the duration
of the frame so that RTSx can be used to enable the RS-422 transceiver.
RTSx
TXDx
SYNC
6-BIT
SEQ
STANDARD HDLC FRAME HANDLING
FLAGS
HDLC
TWO
Figure 16-88. Connecting the MPC823 to AppleTalk
MPC823
ADDR
DEST
MPC823
SCC
Freescale Semiconductor, Inc.
SOURCE
ADDR
For More Information On This Product,
RXDx
TXDx
RTSx
CONTROL
MPC823 REFERENCE MANUAL
BYTE
STORED IN TRANSMIT BUFFER
STORED IN RECEIVE BUFFER
TX ENABLE
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TX DATA
RX DATA
RS-422
DATA
MINI-DIN 8
CRC-16
CLOSING
FLAG
16 ONES
(ABORT)
MOTOROLA