Inverse Multiplexing for ATM (IMA)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 33-27
NOTE

IMAROOT must be programmed to a 128-byte aligned address terminating

with 0x80 (i.e. 0xnn80).

33.4.3 IMA Root Table
Table33 -3. IMA Root Table1
Offset Name Width Description
0x04 IMAFILLERHD24 Bytes Filler cell template. Used by microcode in transmiss ion of filler cells. The
cell is formatted as byte-swapped, and additionally the header is
bitswapped. [This is due to hardware implementation, and does not imply
the order of the transmission of the cell. The transmission of the cell is per
the ATM standard.]
Content should be:
0xD0000000 (header)
0x6A6A0001 or 0x6A6A0003 (for IMA Version 1.0 or 1.1)
0x6A6A6A6A (padding)
0x6A6A6A6A (padding)
0x6A6A6A6A (padding)
0x6A6A6A6A (padding)
0x6A6A6A6A (padding)
0x6A6A6A6A (padding)
0x6A6A6A6A (padding)
0x6A6A6A6A (padding)
0x6A6A6A6A (padding)
0x6A6A6A6A (padding)
0xC6026A6A or 0xD9026A6A (for IMA Version 1.0 or 1.1)
0x00–
0x2F
IMAFILLERPLD 48 Bytes
0x30 FILLTAG Byte Tag indicating that the filler template is a filler cell. Program to zero.
0x31 TQ_SIZE Byte Transmit queue size. Recommended value is 0x18. Must be a multiple of 4.
Refer to Section33.4.6.1, “Transmit Queues for more details
0x32 TQ_TARGET Byte Transmit queue target level. Recommended value is 0x0C. Must be a
multiple of 4.
0x33 TQ_THRESHOLD Byte Transmit queue stuff threshold. Recommended value is 0x0C. Must be a
multiple of 4.
0x34 RESERVED Hword Reserved.
0x36 IMACNTL Byte IMA control parameter. Controls functions shared by all IMA groups for this
FCC.
0x37 TMP_PCNT Byte Microcode managed parameter (pass count).
0x38 RXPHYEN Word Receive PHY enable. Bit array addressed by PHY address (e.g. bit 0
corresponds to PHY 0). Setting a bit enables reception for the
corresponding PHY. Must be used to enable/disable the corresponding
PHY regardless of whether or not the PHY is defined as IMA in IMAPHY.
All cells received by disabled PHYs are discarded. Note that the FCC must
also be enabled in GFMR[ENR] for reception to occur.
Bit 31 is reserved, and must be programmed to zero.