MCF548x Reference Manual, Rev. 3
26-8 Freescale Semiconductor

26.3.3.3 Status Register (PSCSRn)

The PSCSR register indicates the status of the characters in the FIFO and the status of the transmitter and

receiver.

4 TXCTS Transmitter clear-to-send (UART and SIR modes). If both TxCTS and TxRTS are enabled, TxCTS
controls the operation of the transmitter.
0 PSCnCTS has no effect on the transmitter.
1 Enables clear-to-send operation. The transmitter checks the state of PSCnCTS each time it is ready
to send a character. If PSCnCTS is asserted, the character is sent; if it is negated, the channel
PSCnTXD remains in the high state and transmission is delayed until PSCnCTS is asserted.
Changes in PSCnCTS as a character is being sent do not affect its transmission.
3–0 SB Stop-bit length control (UART mode only). Selects the length of the stop bit appended to the transmitted
character. Stop-bit lengths of 9/16th to 2 bits are programmable for 6–8 bit characters. Lengths of 1
1/16th to 2 bits are programmable for 5-bit characters. In all cases, the receiver checks only for a high
condition at the center of the first stop-bit position, that is, one bit time after the last data bit or after the
parity bit, if parity is enabled.
If an external 1x clock is used for the transmitter, clearing bit 3 selects one stop bit and setting bit 3
selects two stop bits for transmission.
An external clock source can be used to generate the baud rate. This is done by configuring the
communications timer. Please refer to the about external clock sources. Also refer to Table 26-6.
15 14 13 12 11 1098 7 6543210
RRB_
NEOF
FE_
PHYERR
PE_
CRCERR
OE TXEMP_
URERR
TX
RDY
FU RX
RDY
CDE_
DEOF
ERR 0 0 0 0 0 0
W
Reset0 0 0 0 0 000 0 0000000
Reg
Addr
MBAR + 0x8604 (PSC0); 0x8704 (PSC1); 0x8804(PSC2); 0x8904 (PSC3)

Figure 26-4. PSC Status Register (PSCSRn)

Table 26-4. PSCMR2n Field Descriptions

Bits Name Description
SB 5
Bits
6–8
Bits
SB 5 Bits 6–8
Bits
SB 5–8
Bits
SB 5–8
Bits
0000 1.063 0.563 0100 1.313 0.813 1000 1.563 1100 1.813
0001 1.125 0.625 0101 1.375 0.875 1001 1.625 1101 1.875
0010 1.188 0.688 0110 1.438 0.938 1010 1.688 1110 1.938
0011 1.250 0.750 0111 1.500 1.000 1011 1.750 1111 2.000