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UART Modules
MCF5272 ColdFire
®
Integrated Microprocessor User’s Manual, Rev. 3
16-14
Freescale Semiconductor
16.3.11 UART Divider Upper/Lower Registers (UDU
n
/UDL
n
)
The UDU
n
registers (formerly called UBG1
n
) hold the MSB, and the UDL
n
registers (formerly UBG2
n
)
hold the LSB of the preload value. UDU
n
and UDL
n
concatenate to provide a divider to CLKIN for
transmitter/receiver operation, as described in
Section 16.5.1.2.1, “CLKIN Baud Rates
.”
NOTE
The minimum value that can be loaded on the concatenation of UDU
n
with
UDL
n
is 0x0002. Both UDU
n
and UDL
n
are write-only and cannot be read
by the CPU.
16.3.12 UART Autobaud Registers (UABU
n
/UABL
n
)
The UABU
n
registers hold the MSB, and the UABL
n
registers hold the LSB of the calculated baud rate.
If UCR
n
[ENAB] is set, the value in these registers is automatically loaded into UDU
n
and UDL
n
.
7
0
Field
Divider MSB
Reset
0000_0000
R/W
Write only
Address
MBAR + 0x118 (UDU0), 0x158 (UDU1)
Figure 16-12. UART Divider Upper Registers (UDU
n
)
7
0
Field
Divider LSB
Reset
0000_0000
R/W
Write only
Address
MBAR + 0x11C (UDL0), 0x15C (UDL1)
Figure 16-13. UART Divider Lower Registers (UDL
n
)
7
0
Field
Autobaud MSB
Reset
0000_0000
R/W
Read only
Address
MBAR + 0x120 (UABU0), 0x160 (UABU1)
Figure 16-14. UART Autobaud Upper Registers (UABU
n
)
7
0
Field
Autobaud LSB
Reset
0000_0000
R/W
Read only
Address
MBAR + 0x124 (UABL0), 0x164 (UABL1)
Figure 16-15. UART Autobaud Lower Registers (UABL
n
)