PM7347 datasheet(280/341 Pages) PMC

280 / 341 page

S/UNI®-JET Data Sheet

Released

Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use

280

Document ID: PMC-1990267, Issue 3

The TDPR will force transmission of the packet information when the FIFO depth exceeds the

threshold programmed with the UTHR[6:0] bits in the TDPR Upper Transmit Threshold Register.

Unless an error condition occurs, transmission will not stop until the last byte of all complete

packets is transmitted and the FIFO depth is at or below the threshold limit. The user should

watch the FULLI and LFILLI interrupts to prevent overruns and underruns.

13.12.2

TDPR Interrupt Routine

Upon assertion of INTB, the source of the interrupt must first be identified by reading the S/UNI-

JET Clock Activity Monitor and Interrupt Identification Register (007H) and the S/UNI-JET

Interrupt Status Registers (005H, 105H, 205H, 305H). Once the source of the interrupt has been

identified as TDPR, do the following procedure:

• Read the TDPR Interrupt Status Register.

• If UDRI=1, then the FIFO has underrun and the last packet transmitted has been corrupted

and needs to be retransmitted. When the UDRI bit transitions to logic one, one Abort

sequence and continuous flags will be transmitted. The TDPR FIFO is held in reset state. To

reenable the TDPR FIFO and to clear the underrun, the TDPR Interrupt Status/UDR Clear

• If OVRI=1, then the FIFO has overflowed. The packet which the last byte written into the

FIFO belongs to has been corrupted and must be retransmitted. Other packets in the FIFO are

not affected. Either a timer can be used to determine when sufficient bytes are available in the

FIFO or the user can wait until the LFILLI interrupt is set, indicating that the FIFO depth is at

the lower threshold limit.

If the FIFO overflows on the packet currently being transmitted (packet is greater than 128 bytes

long), OVRI is set, an Abort signal is scheduled to be transmitted, the FIFO is emptied, and then

flags are continuously sent until there is data to be transmitted. The FIFO is held in reset until a

write to the TDPR Transmit Data Register occurs. This write contains the first byte of the next

packet to be transmitted.

If FULLI=1 and FULL=1, then the TDPR FIFO is full and no further bytes can be written. When

in this state, either a timer can be used to determine when sufficient bytes are available in the

FIFO or the user can wait until the LFILLI interrupt is set, indicating that the FIFO depth is at the

lower threshold limit.

If FULLI=1 and FULL=0, then the TDPR FIFO had reached the FULL state earlier, but has since

emptied out some of its data bytes and now has space available in its FIFO for more data.

If LFILLI=1 and BLFILL=1, then the TDPR FIFO depth is below its lower threshold limit. If

there is more data to transmit, then it should be written to the TDPR Transmit Data Register

before an underrun occurs. If there is no more data to transmit, then an EOM should be set at the

end of the last packet byte. Flags will then be transmitted once the last packet has been

transmitted.

If LFILLI=1 and BLFILL=0, then the TDPR FIFO had fallen below the lower-threshold state

earlier, but has since been refilled to a level above the lower-threshold level.

PM7347 Datasheet(PDF) 280 Page - PMC-Sierra, Inc

PM7347 Datasheet(HTML) 280 Page - PMC-Sierra, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL