28478G-18 Mindspeed Technologies, 28478G-18 Datasheet - Page 106

• Manufacturer Part Number: 28478G-18
• Description: Multichannel Synchronous Communications Controller 208-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of 28478G-18

• Package: 208BGA
• Maximum Data Rate: 32768 Kbps
• Transmission Media Type: Wire
• Power Supply Type: Analog
• Typical Supply Current: 250 mA
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3 V
• Maximum Operating Supply Voltage: 3.6 V

Table 5-18.
5.2.4
One message descriptor defines one data buffer where all or part of a message is stored in shared memory. By
linking message descriptors, numerous data buffers are linked to support high-speed data links or large messages
spread across a number of smaller data buffers.
Depending on the transmission and reception rate of individual channels, the numbers and sizes of message
buffers can vary between channels and applications. For high-speed lines, more and larger buffers can be used to
provide ample data storage while the host processes each message in the list of messages. For low-speed lines,
fewer and smaller buffers can be used as the host may be able to process each message faster and the need to
store messages is lessened.
Multiple smaller data buffers can be linked using message descriptors to store one large message. In utilizing
multiple buffers, the importance of keeping the sequence of data buffers in order is obvious.
MUSYCC’s operation allows for the following:
•
•
•
•
A message descriptor is designed to be usable by both the transmit and receive functions in MUSYCC. In providing
this symmetry, a mechanism known as self-servicing buffers is available, which allows the reuse of a single
descriptor for both the transmit and receive portions of a channel, and is designed for diagnostics and loopback
capabilities.
Table 5-19.
28478-DSH-002-E
Field
Bit
Multiple buffer lists
Multiple and variable size buffers within a buffer list
Multiple buffers storing a single message
Sequencing of individual data buffers for a multi-buffer message
1
0
Byte Offset
Table 5-19
00h
04h
08h
Channel Configuration Descriptor (3 of 3)
Message Descriptor
—
MSKBUFF
Name
RSVD
Message Level Descriptor
lists the message descriptor details.
Preliminary Information / Mindspeed Proprietary and Confidential
Buffer Descriptor (Host Writes)
Buffer Status Descriptor (MUSYCC Writes)
Data Pointer
Next Pointer
Value
0
1
0
Mindspeed Technologies
BUFF—Interrupts enabled. Receive and Transmit. Interrupt generated when transmitter
underflow buffer or receiver overflows buffer internally to MUSYCC.
ONR—Interrupts enabled. Receive and Transmit. Interrupt generated where message
pointer/descriptor is not available to MUSYCC where is expected. (Refer to
31, Interrupt
BUFF—Interrupts disabled. ONR—Interrupts disabled.
Reserved.
Field Name
TOTAL
Descriptor.)
®
Description
dwords
1
1
1
3
Memory Organization
Figure 5-
Bytes
12
4
4
4
93