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Serial Management Controllers (SMCs)
MC68360 USER’S MANUAL
contains five 8-bit characters. Write $B000 to Tx_BD_Status. Write $0005 to
Tx_BD_Length. Write $00002000 to Tx_BD_Pointer.
7. Write $FF to the SMCE to clear any previous events.
8. Write $13 to the SMCM to enable all possible SMC interrupts.
9. Write $00000010 to the CIMR to allow SMC1 to generate a system interrupt. (The
CICR should also be initialized.)
10. Write $3830 to SMCMR to configure 8-bit characters, non-reversed data, and normal
operation (not loopback). Notice that the transmitter and receiver have not been
enabled yet.
11. Write $3833 to SMCMR to enable the SMC transmitter and receiver. This additional
write ensures that the TEN and REN bits will be enabled last.
NOTE
After 5 bytes have been transmitted, the Tx BD is closed. Addi-
tionally, the receive buffer is closed after 16 bytes have been re-
ceived. Any additional receive data beyond 16 bytes will cause
a busy (out-of-buffers) condition since only one Rx BD was pre-
pared.
7.11.13 SMC Interrupt Handling
The following list describes what would normally occur within an interrupt handler for the
SMC.
1. Once an interrupt occurs, read the SMCE to see which sources have caused inter-
rupts. The SMCE bits would normally be cleared at this time.
2. Process the Tx BD to reuse it if the TX bit was set in SMCE. Extract data from the Rx
BD if the RX bit was set in SMCE. To transmit another buffer, simply set the Tx BD R-
bit.
3. Clear the SMC1 bit in the CISR.
4. Execute the RTE instruction.
7.11.14 SMC as a GCI Controller
The SMC can be used to control the C/I and to monitor channels of the GCI frame. When
using the SCIT configuration of GCI, one SMC can handle SCIT channel 0, and the other
SMC can handle SCIT channel 1. The main features are as follows:
Each SMC Channel Supports the C/I and Monitor Channels of the GCI (IOM-2) in ISDN
Applications
Two SMCs Support the Two Sets of C/I and Monitor Channels in SCIT Channel 0 and
Channel 1
Full-Duplex Operation
Local Loopback and Echo Capability for Testing
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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