MCF548x Reference Manual, Rev. 3
26-16 Freescale Semiconductor

Table 26-8 shows the fields for Modem 8, SIR, MIR, and FIR modes.

Table 26-9 shows the fields for Modem 16 mode.

Table 26-10 shows the fields for AC 97 mode.

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R RB[19:4]
WTB[19:4]
Reset0000000000 0 0 0 0 00
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
R RB[3:0] SOF 0 0 0 0 0 0 0 0 0 0 0
W TB[3:0]
Reset0000000000 0 0 0 0 00
Reg
Addr
MBAR + 0x860C (PSC0); 0x870C (PSC1); 0x880C (PSC2); 0x890C (PSC3)

Figure 26-11. Receiver (PSCRBn) and Transmitter (PSCTBn) Buffer Register for AC97 Mode

Table 26-8. PSCRBn and PSCTBn Field Descriptions for UART,

Modem 8, SIR, MIR, and FIR Modes

Bits Name Description
31–0 RB Received data—For these modes, data can be read one, two, or four bytes at a time. For one byte
at a time, bytes must be read from bits 31–24. For two bytes at a time, bytes must be read from bits
31–16. Higher-bit data was received before lower-bit data.
TB Transmit data—For these modes, data can be written one, two, or four bytes at a time. For one byte
at a time, bytes must be written to bits 31–24. For two bytes at a time, bytes must be written to bits
31–16. Higher-bit data is transmitted before lower-bit data.

Table 26-9. PSCRBn and PSCTBn Field Descriptions for Modem 16 Mode

Bits Name Description
31–0 RB Received data—For these modes, data can be read two or four bytes at a time. For two bytes at a
time, bytes must be read from bits 31–16. Higher-bit data was received before lower-bit data.
TB Transmit data—For these modes, data can be written two or four bytes at a time. For two bytes at
a time, bytes must be written to bits 31–16. Higher-bit data is transmitted before lower-bit data.

Table 26-10. PSCRBn and PSCTBn AC 97 Mode Field Descriptions

Bits Name Description
31–12 RB Received data—AC97 data must be read one complete sample at a time. All samples except
timeslot #0 (TAG slot) are 20 bits. Timeslot #0 data is only 16 bits. The SOF bit indicates the start
of a frame.
TB Transmit data—AC97 data must be written one complete sample at a time. All samples except
timeslot #0 (TAG slot) are 20 bits. Timeslot #0 data is only 16 bits. The SORF bit indicates the start
of a frame