STLC5464 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
STLC5464 Datasheet PDF : 83 Pages
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STLC5464
IX - EXTERNAL REGISTERS (continued)
IX.2 - Receive Descriptor
This receive descriptor is located in shared memory. The quantity of descriptors is limited by the memory
size only.
15
RDA+00
RDA+02
RDA+04
14
13
12 11 10 9 8 7 6 5 4 3 2 1 0
IBC EOQ
Size Of the Buffer (SOB)
0
Not used
RBA High (8 bits)
Receive Buffer Address Low (16 bits)
RDA+06
Not used
NRDA High (8 bits)
RDA+08
Next Receive Descriptor Address Low (16 bits)
RDA+10 FR ABT OVF FCRC
Number of Bytes Received (NBR)
The 5 first words located in shared memory to RDA+00 from RDA+08 are written by the microprocessor
and read by the DMAC only. The 6th word located in shared memory in RDA+10 is written by the DMAC
only during the frame reception and read by the microprocessor.
SOB : Size Of the Buffer associated to descriptor up to 2048 words (1 word = 2 bytes).
If SOB = 0, DMAC goes to next descriptor.
RBA : Receive Buffer Address. LSB of RBA Low is at Zero mandatory.
RDA : Receive Descriptor Address.
NRDA : Next Receive Descriptor Address. LSB of NRDA Low is at Zero mandatory.
NBR : Number of Bytes Received (up to 4096).
IX.2.1 - Bits written by the Microprocessor only
IBC
EOQ
: Interrupt if the buffer has been completed.
IBC=1, the DMAC generates an interrupt if the buffer has been completed.
: End Of Queue.
EOQ=1, the DMAC stops immediately its reception generates an interrupt (HDLC = 1 in IR) and
waits a command from the HRCR (HDLC Receive Command Register).
EOQ=0, the DMAC continues.
IX.2.2 - Bits written by the Rx DMAC only
FR ABT OVF FCRC
Definition
1
0
0
0 The frame has been received without error. The end of frame is in this buffer.
1
0
0
1 The frame has been received with false CRC.
0
0
0
0 If NBR is different to 0, the buffer related to this descriptor is completed.The end
of frame is not in this buffer.
0
0
0
0 If NBR is equal to 0, the Rx DMAC is receiving a frame.
0
1
0
0 ABORT. The received frame has been aborted by the remote transmitter or the
local microprocessor.
0
1
1
0 OVERFLOW of FIFO. The received frame has been aborted.
0
1
0
1 The received frame had not an integer of bytes.
IX.2.3 - Receive Buffer
Each receive buffer is defined by its receive descriptor.
The maximum size of the buffer is 2048 words (1 word=2 bytes)
15
0
RBA
First Buffer Location
RBA + SOB-2
Last Location Available = Recive Buffer Address (RBA) + Size Of the Buffer (SOB-2)
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