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UART Modules
MCF5272 ColdFire
®
Integrated Microprocessor User’s Manual, Rev. 3
Freescale Semiconductor
16-17
16.3.15 UART Fractional Precision Divider Control Registers (UFPD
n
)
The UFPD
n
registers allow greater accuracy when deriving a transmitter/receiver clock source from
CLKIN. The use of the UFPD
n
registers is optional; if the contents are left in the reset state, code written
for other ColdFire devices containing UART modules will not be affected by the addition of these
registers. The contents of these registers allow the frequency to be divided by a factor of up to 16. When
autobaud is used, these registers are updated automatically to reflect the clock rate being used. Host
software can write to these registers to make fine adjustments to the clock rate. See
n
programming.
describes UFPD
n
fields.
16.3.16 UART Input Port Registers (UIP
n
)
The UIP
registers,
, show the current state of the CTS input.
describes UIP
n
fields.
7
4
3
0
Field
—
FD
Reset
0000_0000
R/W
R/W
Address
MBAR + 0x130 (UFPD0), 0x170 (UFPD1)
Figure 16-18. UART Fractional Precision Divider Control Registers (UFPD
n
)
Table 16-12. UFPD
n
Field Descriptions
Bits
Name
Description
7–4
—
Reserved, should be cleared.
3–0
FD
Fractional divider. The value of these bits, from 0 to 15, determine the scale factor by which the clocking source
for the transmitter and/or receiver is scaled.
7
1
0
Field
—
CTS
Reset
1111_1111
R/W
Read only
Address
MBAR + 0x134 (UIP0), 0x174 (UIP1)
Figure 16-19. UART Input Port Registers (UIP
n
)
Table 16-13. UIP
n
Field Descriptions
Bits
Name
Description
7–1
—
Reserved, should be cleared.
0
CTS
CTS state.The CTS value is latched and reflects the state of the input pin when UIP
n
is read. Note: This bit
has the same function and value as UIPCR
n
[RTS].
0 The current state of the CTS input is logic 0.
1 The current state of the CTS input is logic 1.