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Serial Management Controllers (SMCs)
7-292
MC68360 USER’S MANUAL
Continuous Transmission and Reception Modes
Four Commands
7.11.10.2 SMC TRANSPARENT COMPARISON. As compared to the transparent modes
supported by the SCCs, the SMCs offer less functionality. This fits with their purpose of pro-
viding simpler functions and slower speeds. The SMC transparent controller does not sup-
port the following features:
Independent Transmit and Receive Clocks Unless Connected to a TDM Channel of the
SI
CRC Generation and Checking
Full RTS, CTS, and CD Pins—Supports One SMSYN Pin Only
Ability To Transmit Data on Demand using the TODR
Receiver/Transmitter in Transparent Mode While Receiver/Transmitter Executes An-
other Protocol
4-, 8-, or 16-Bit SYNC Recognition
Internal DPLL Support
Other Features for the SCCs As Described in the GSMR
The SMCs in transparent mode, however, do provide one feature not provided by the regular
SCCs. The SMCs allow a data character length option of 4 to 16 bits; whereas, the SCCs
provide a data character length of just 8 or 32 bits (determined by the RFW bit in the GSMR).
7.11.10.3 SMC TRANSPARENT MEMORY MAP. There is no protocol-specific parameter
RAM for the SMC when it is used as a transparent controller. Only the general SMC param-
eter RAM is used, which is discussed in 7.11.4 SMC Parameter RAM.
7.11.10.4 SMC TRANSPARENT TRANSMISSION PROCESSING. The transparent trans-
mitter is designed to work with almost no intervention from the CPU32+ core. When the
CPU32+ enables the SMC transmitter in transparent mode, it will start transmitting idles.
The SMC immediately polls the first BD in the transmit channel’s BD ring, and thereafter
once every character time, depending on the character length (i.e., every 4 to 16 serial
clocks). When there is a message to transmit, the SMC controller will fetch the data from
memory and start transmitting the message once synchronization is achieved.
Table 7-14. SMC Transparent-Specific
Parameter RAM
Address
Name
Width
Description
SMC Base + 28
Reserved
Word
Reserved
SMC Base + 2A
Reserved
Word
Reserved
SMC Base + 2C
Reserved
Word
Reserved
SMC Base + 2E
Reserved
Word
Reserved
SMC Base + 30
Reserved
Word
Reserved
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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