XRT84L38 View Datasheet(PDF) - Exar Corporation
Part Name
Description
MFG CO.
'XRT84L38' PDF : 453 Pages View PDF
XRT84L38
REV. 1.0.1
OCTAL T1/E1/J1 FRAMER
1.0 MICROPROCESSOR INTERFACE BLOCK
The Microprocessor Interface section supports communication between the local microprocessor (µP) and the
Framer. The Microprocessor Interface supports the following features:
• Communicates through a 7 bit address bus (4 bit for one framer) and an 8 bit data bus.
• Supports DMA read/write data interface
• Supports burst transfers
• Supports Programmed I/O read and write, wait cycle extended with READY/DTACK
The Microprocessor Interface section supports the following operations:
• Channel Selection
• Writing configuration data into the Framer on-chip (addressable) registers
• Writing outbound PMDL (Path Maintenance Data Link) messages into the Transmit LAPD Message buffer of
the Framer
• Generation of Interrupt Requests to the µP
• Servicing Interrupt Requests from the Framer
• Monitoring the system's health by periodically reading the on-chip Performance Monitor registers
• Reading inbound PMDL Messages from the Receive LAPD Message Buffer of the Framer
Each of these operations (between the local microprocessor and the Framer IC) is discussed in detail,
throughout this data sheet.
The Framer supports the following microprocessors/microcontrollers with a minimum amount of glue logic.
• Intel 8051, 80C188, x86, i960
• Motorola 68HC11, 68K
• MIPS 3051/52
• PowerPC 403
The type of microprocessor/microcontroller to interface to the Framer is specified by tying the μPTYPE[2:0]
pins to the appropriate level. Table 1, lists the values for μPTYPE[2:0] and the corresponding µP/µC types.
TABLE 3: µC/µP SELECTION TABLE
μPTYPE[2:0] INPUT LEVELS
000
001
010
011
100
101
CORRESPONDING μC/μP
68HC11, 8051, 80C188
Motorola 68000 Family
Intel x86 Family
Intel I960
IDT3051/52 (MIPS)
IBM PowerPC 403
The behavior of some of the pins, associated with the Microprocessor Interface, depends upon the value that
the user has applied to the PType[2:0] input pins. The next sections present a detailed discussion on the role of
each of these pins, and how to configure the Framer to interface to each of these types of Microprocessors.
The Framer connects to the Microcontroller as if it were external memory. The microcontroller can read or write
to two different storage elements in the Framer:
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