Serial Management Controllers (SMCs)
MPC885 PowerQUICC Family Reference Manual, Rev. 2
29-20
Freescale Semiconductor
11. Set BRKCR to 0x0001; if a
STOP
TRANSMIT
COMMAND
is issued, one break character is sent.
12. Initialize the RxBD. Assume the Rx buffer is at 0x0000_1000 in main memory. Write 0xB000 to
Rx_BD_Status, 0x0000 to Rx_BD_Length (not required), and 0x0000_1000 to Rx_BD_Pointer.
13. Assuming the Tx buffer is at 0x00002000 in main memory and contains five 8-bit characters, write
0xB000 to Tx_BD_Status, 0x0005 to Tx_BD_Length, and 0x00002000 to Tx_BD_Pointer.
14. Write 0xFF to the SMCE register to clear any previous events.
15. Write 0x17 to the SMCM register to enable all possible SMC interrupts.
16. Write 0x00000010 to the CIMR so the SMC1 can generate a system interrupt. Initialize the CICR.
17. Write 0x4820 to SMCMR to configure normal operation (not loopback), 8-bit characters, no parity,
1 stop bit. The transmitter and receiver are not yet enabled.
18. Write 0x4823 to SMCMR to enable the SMC transmitter and receiver. This additional write
ensures that the TEN and REN bits are enabled last.
After 5 bytes are sent, the TxBD is closed. The receive buffer closes after receiving 16 bytes. Subsequent
data causes a busy (out-of-buffers) condition since only one RxBD is ready.
29.4
SMC in Transparent Mode
Compared to the SCC in transparent mode, the SMCs generally have less functionality, simpler functions
and slower speeds. Transparent mode is selected by setting SMCMR[SM] to 0b11.
Section 29.2.1, “SMC
Mode Registers (SMCMRn),”
describes other protocol-specific bits in the SMCMR. The SMC in
transparent mode does not support 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 signals (supports only one SMSYN signal)
•
Ability to transmit data on demand using the TODR
•
Receiver/transmitter in transparent mode while executing another protocol
•
4-, 8-, or 16-bit SYNC recognition
•
Internal DPLL support
However, the SMC in transparent mode provides a data character length option of 4 to 16 bits, whereas the
SCCs provide 8 or 32 bits, depending on GSMR[RFW]. The SMC in transparent mode is also referred to
as the SMC transparent controller.
29.4.1
SMC Transparent Mode Features
The following list summarizes the features of the SMC in transparent mode:
•
Flexible buffers
•
Can connect to a TDM bus using the TSA in the SI
•
Can transmit and receive transparently on its own set of pins using a sync pin to synchronize the
beginning of transmission and reception to an external event
•
Programmable character length (4–16)
Summary of Contents for PowerQUICC MPC870
Page 98: ...MPC885 PowerQUICC Family Reference Manual Rev 2 I 4 Freescale Semiconductor ...
Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Page 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
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Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...