28478G-18 Mindspeed Technologies, 28478G-18 Datasheet - Page 166

• 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

When receiving an unerrored message with a payload length of 3, 4, or 5 octets and the required 2-octet FCS,
MUSYCC transfers the data into the memory buffer as usual and then enters the message filtering mode. This
mode does not apply to messages with payloads greater than 5 octets.
In this mode, the next Message Descriptor is processed in the normal manner (receive Buffer Status Descriptor is
written, next pointer is used to read next Message Descriptor, ONR and NP bits are checked, and so on). In this
case, the current memory buffer is not filled until MUSYCC exits the message filtering mode.
The 3-, 4-, or 5-octet payload and the 2-octet FCS are stored inside MUSYCC and are considered golden
messages by being 3, 4, or 5 octets long. Subsequent received messages are compared to this message.
Each bit of the subsequent message will be compared bit-wise to the contents of the golden message. The
following can occur:
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•
The treatment for the current message becomes a normal message treatment. If the current message is unerrored
and qualifies to become a golden message, it is transferred to the current Receive Data Buffer and becomes the
new golden message internally to MUSYCC.
If the current message is unerrored and greater than 6 octets total, it cannot become a golden message, and
MUSYCC continues normal message treatment.
6.5.3
The Signal Unit Error Rate Monitor (SUERM) facility provides a 6-bit counter which serves as a real-time figure-of-
merit for the receive link integrity. It is incremented and decremented in a “leaky-bucket” style, based upon
integration of good message and bad octet periods on the receive channel.
6.5.4
The SUERM counter increments when any signal unit error occurs. A signal unit error is defined as one of the
following events:
•
•
•
•
Short Frame errors, Octet Alignment errors, or CRC/FCS Mismatch errors generate a maskable interrupt, SHT,
LNG, CRC respectively, toward the host and cause the SUERM counter to be incremented. Each time the SUERM
counter is incremented, the maskable interrupt SINC is generated to the host indicating this condition.
6.5.5
Octet counting mode is entered if seven consecutive 1s are detected (abort condition), or the received message
length exceeds the selected maximum received-frame length register value (long frame error)
28478-DSH-002-E
If a match occurs, the payload and FCS of the golden message match the current message before a closing
flag is received for the current message. The maskable interrupt MSKSFILT is generated to the host. MUSYCC
remains in message filtering mode, and the golden message is retained.
If a mismatch occurs, a bit-wise mismatch is detected between a bit in the golden message and the
corresponding bit in the current message before a closing flag is received for the current message. MUSYCC
immediately exits the filter mode.
SHT:
ALIGN: Octet Alignment error
CRC:
Accumulation of 16 octet count errors
Short Frame error
FCS Mismatch error
Signal Unit Error Rate Monitoring
SUERM Counter Incrementing
SUERM Octet Counting
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