MC68MH360EM33L Freescale Semiconductor, MC68MH360EM33L Datasheet - Page 550

• Manufacturer Part Number: MC68MH360EM33L
• Description: IC MPU QUICC ETHER 33MHZ 240FQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68MH360EM33L

• Processor Type: M683xx 32-Bit
• Speed: 33MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 240-FQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -

Serial Communication Controllers (SCCs)
CRC_P. For the 16-bit CRC-CCITT, CRC_P should be initialized with $0000FFFF. For the
32-bit CRC-CCITT, CRC_P should be initialized with $FFFFFFFF. For the CRC-16, CRC_P
should be initialized with ones ($0000FFFF) or zeros ($00000000).
CRC_C. For the 16-bit CRC-CCITT, CRC_C should be initialized with $0000F0B8. For the
32-bit CRC-CCITT, CRC_C should be initialized with $DEBB20E3. For the CRC-16 which
is normally used with BISYNC, CRC_C should be initialized with $00000000.
7.10.21.6 TRANSPARENT COMMAND SET. The following transmit and receive com-
mands are issued to the CR.
7.10.21.6.1 Transmit Commands. The following paragraphs describe the transparent
transmit commands.
STOP TRANSMIT Command . After a hardware or software reset and the enabling of the
channel in the SCC mode register, the channel is in the transmit enable mode and starts
polling the first BD in the table every 64 clocks (immediately if the TOD bit in the TODR is
set).
The STOP TRANSMIT command disables the transmission of frames on the transmit chan-
nel. If this command is received by the transparent controller during frame transmission,
transmission of that buffer is aborted after a maximum of 64 additional bits are transmitted,
and the transmit FIFO is flushed. The TBPTR is not advanced, no new BD is accessed, and
no new buffers are transmitted for this channel. The transmitter will send idles.
GRACEFUL STOP TRANSMIT Command . The GRACEFUL STOP TRANSMIT command
is used to stop transmission in an orderly way, rather than abruptly as performed by the reg-
ular STOP TRANSMIT command. It stops transmission after the current frame has com-
pleted transmission, or immediately if there is no frame being transmitted. (A transparent
frame is not complete until a BD with the L-bit set has its associated buffer completely trans-
mitted.) The GRA bit in the SCCE will be set once transmission has stopped. After transmis-
sion ceases, the transmit parameters, including BDs, may be modified. The TBPTR will point
to the next Tx BD in the table. Transmission will begin once the R-bit of the next BD is set
and the RESTART TRANSMIT command is issued.
RESTART TRANSMIT Command . The RESTART TRANSMIT command reenables the
transmission of characters on the transmit channel. This command is expected by the trans-
parent controller after a STOP TRANSMIT command, after a STOP TRANSMIT command
and disabling the channel in its SCC mode register, after a GRACEFUL STOP TRANSMIT
7-226
This value overlaps with the CRC constant (mask) for the HDLC-
based protocols. This overlap is not detrimental since the CRC
constant (mask) is only used for the receiver; thus, only one en-
try is required. Therefore, the user may choose HDLC transmit-
ter with a transparent receiver or a transparent transmitter with
an HDLC receiver.
Freescale Semiconductor, Inc.
For More Information On This Product,
MC68360 USER’S MANUAL
Go to: www.freescale.com
NOTE
MOTOROLA