Motorola PowerQUICC II MPC8280 Series Reference Manual page 826

SCC2 Transparent Programming Example
Table 24-10 describes SCCS fields.
Bit Name
0–5 — Reserved, should be cleared.
6 CS Carrier sense (DPLL). Shows the real-time carrier sense of the line as determined by the DPLL.
0 The DPLL does not sense a carrier.
1 The DPLL senses a carrier.
7 — Reserved, should be cleared.
24.14 SCC2 Transparent Programming Example
The following initialization sequence enables the transmitter and receiver, which operate
independently of each other. They implement the connection shown on MPC8280 (B) in
Figure 24-1.
The transmit and receive clocks are externally provided to MPC8280 (B) using CLK3.
SCC2 is used. The transparent controller is configured with the RTS2 and CD2 pins active
and CTS2 is configured to be grounded internally. A 16-bit CRC-CCITT is sent with each
transparent frame. The FIFOs are configured for fast operation.
1. Configure port D pins to enable TXD2 and RXD2. Set PPARD[27,28] and
PDIRD[27] and clear PDIRD[28] and PSORD[27,28].
2. Configure ports C and D pins to enable RTS2, CTS2 and CD2. Set PPARD[26],
PPARC[12,13] and PDIRD[26] and clear PDIRC[12,13], PSORC[12,13] and
PSORD[26].
3. Configure port C pin 29 to enable the CLK3 pin. Set PPARC[29] and clear
PDIRC[29] and PSORC[29].
4. Connect CLK3 to SCC2 using the CPM mux. Program CMXSCR[R2CS] and
CMXSCR[T2CS] to 0b110.
5. Connect the SCC2 to the NMSI and clear CMXSCR[SC2].
6. Write RBASE with 0x0000 and TBASE with 0x0008 in the SCC2 parameter RAM
to point to one RxBD at the beginning of dual-port RAM followed by one TxBD.
7. Write 0x04A1_0000 to the CPCR to execute
SCC2.
8. Write 0x0041 to the CPCR to execute
9. Write RFCR and TFCR with 0x10 for normal operation.
10. Write MRBLR with the maximum number of bytes per receive buffer and assume
16-bytes, so MRBLR = 0x0010.
11. Write CRC_P with 0x0000_FFFF to comply with the 16-bit CRC-CCITT.
12. Write CRC_C with 0x0000_F0B8 to comply with the 16-bit CRC-CCITT.
24-14
Freescale Semiconductor, Inc.
Table 24-10. SCCS Field Descriptions
MPC8280 PowerQUICC II Family Reference Manual
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Description
INIT RX AND TX PARAMETERS
INIT RX AND TX PARAMETERS
for
for SCC2.
MOTOROLA