cx28365 Mindspeed Technologies, cx28365 Datasheet - Page 77

• Manufacturer Part Number: cx28365
• Description: X12, X6, X4 T3/e3 Framer And Atm Cell Transmission Convergence Sublayer Processor
• Manufacturer: Mindspeed Technologies

CX28365/6/4 Data Sheet
Table 2-7. Status Byte Description
500028C
Field Value
Set
Cleared
GENERAL NOTE:
discarded by the RDL. Also, if one or more a2 blocks is followed by a b block, all the data bytes of the previously read a2 blocks
belong to the same erroneous/aborted message.
RxGoodBlk
—
Set
Cleared
Undefined
In type b, the number of data bytes in the block is always 0, as the data bytes are of no significance and therefore
MSB
interface either in interrupt-driven mode, using maskable interrupts to synchronize
data flow into and out of the FIFO buffer, or in status-polling mode.
The RDL FIFO buffer contains two types of information, data bytes and status bytes.
Data bytes are the actual data extracted from the DL channel (all flag-bounded bytes
except flag and abort sequences and zeros for transparency). Status bytes contain
additional information qualifying the data bytes following them.
A data block within the FIFO buffer is one status byte followed by 0 to 127 data bytes.
When a new block starts, the RDL reserves one byte for status and then fills data
bytes, as required, until the end of the block. At the end, status information is written
into the reserved byte and a new block is started.
A block terminates and a new one starts in conjunction with one of the following:
Before the status byte is read from the RxMsgByte Status register, the user must read
the RDL Status register and get the RxGoodBlk field value. This bit defines the type
of the status byte to be read from the RxMsgByte Status register.
For types a1 and a2, the RxGoodBlk is set; for type b it is cleared. Refer to
The available RDL-related interrupt events are as follows:
Type
Preliminary Information/Mindspeed Proprietary and Confidential
A FIFO near-full interrupt
A message received interrupt
A FIFO overrun interrupt
a1
a2
FIFO near-full:
b
Turned on when the number of bytes in the FIFO buffer is equal to or more than
the programmable Near-Full FIFO threshold (range = 2 to 127). A type a2
block ends when this interrupt is turned on, and another block of this type is
not be produced until the interrupt is turned off].
Turned off when there are no more unread complete blocks left in the FIFO
buffer, i.e., when the last byte of the last complete data block has been read: If,
after reading all pending complete blocks from the FIFO buffer, the number of
End of message (detection of flag sequence) with
correct FCS
Partially-received message, FIFO near-full, message
data continue in next block
Errored block cases: end of message with incorrect
FCS, or end of message with number of bits
indivisible by 8 (alignment error), or aborted
message (detection of abort sequence), or overrun
error.
Priority of error type is bad FCS, align error, abort,
overrun (from low to high). Only one type of error
can be indicated.
Mindspeed Technologies™
Description
Number of data bytes in block
(range = 0 to 127)
Additional Information
(Bits 0–6)
Functional Description
—
—
Table
2-7.
2
-
39