Freescale Semiconductor MPC8260 - Manual (Page 853)

Multi-Channel Controllers (MCCs)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 28-5
28.3 Channel-Specific Parameters
Each FIFO in the MCC is managed by a set of channel-specific parameters. These parameters can change
based upon what protocol is being used on that channel. The following sections describe the various
programming models used for an MCC channel.
28.3.1 Channel-Specific HDLC Parameters
Table 28-2 describes channel-specific parameters for HDLC.
0x28 C_MASK32 Word CRC constant (user initialized to 0xDEBB20E3). Used for 32-bit CRC-CCITT
calculation if HDLC mode is chosen for a selected channel. (This option is
programmable. For each HDLC channel, one of two CRC-CCITT can be selected
through the CHAMR.)
0x2C XTRABASE Hword Pointer the beginning of the extra parameters information, offset from the DPRAM
address
0x2E C_MASK16 Hword CRC constant (user initialized to 0xF0B8). Used for 16-bit CRC-CCITT calculation if
HDLC mode is chosen for a selected channel. This option is programmable. For each
HDLC channel, one of two CRC-CCITT can be selected through the CHAMR.
0x30 RINTTMP0 Word RINTTMPx. Temporary location for holding a receive circular interrupt circular table
entry (for tables 0–4), used by the CP. The user must clear it before enabling
interrupts. See
Section 28.8, “MCC Exceptions .”
0x34 RINTTMP1 Word
0x38 RINTTMP2 Word
0x3C RINTTMP3 Word
0x40 RINTBASE0 Word RINTBASEx—Multi-channel receiver circular interrupt table base address. The
interrupt circular table is a cyclic table (FIFO-like). Each table entry contains
information about an interrupt request generated by the MCC to the host.
RINTPTRx—Pointer to the receiver circular interrupt table. The CP writes the next
interrupt information to this entry when an exception occurs. The user must copy the
RINTBASEx value to RINTPTRx before enabling interrupts. Further updates of the
RINTPTRx are done by the CP.
0x44 RINTPTR0 Word
0x48 RINTBASE1 Word
0x4C RINTPTR1 Word
0x50 RINTBASE2 Word
0x54 RINTPTR2 Word
0x58 RINTBASE3 Word
0x5C RINTPTR3 Word
0x60 TS_TMP Word Temporary place for time stamp
1
Offset to MCC Base
Table 28-1. Global MCC Parameters (continued)
Offset
1
Name Width Description