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UART Modules
MCF5213 ColdFire® Integrated Microcontroller Reference Manual, Rev. 3
21-16
Freescale Semiconductor
21.3.13 UART Output Port Command Registers (UOP1
n
/UOP0
n
)
The U
n
RTS output can be asserted by writing a 1 to UOP1
n
[RTS] and negated by writing a 1 to
UOP0
n
[RTS]. See
21.4
Functional Description
This section describes operation of the clock source generator, transmitter, and receiver.
21.4.1
Transmitter/Receiver Clock Source
The internal bus clock serves as the basic timing reference for the clock source generator logic, which
consists of a clock generator and a programmable 16-bit divider dedicated to each UART. The clock
generator might not produce standard baud rates if the internal bus clock is used, so the user must enable
the 16-bit divider.
Table 21-11. UIP
n
Field Descriptions
Field
Description
7–1
Reserved
0
CTS
Current state of clear-to-send. The U
n
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 U
n
CTS input is logic 0.
1 The current state of the U
n
CTS input is logic 1.
IPSBAR
Offset:
0x00_0238 (UOP10)
0x00_023C (UOP00)
0x00_0278 (UOP11)
0x00_027C (UOP01)
0x00_02B8 (UOP12)
0x00_02BC (UOP02)
Access: User write-only
7
6
5
4
3
2
1
0
R
W
0
0
0
0
0
0
0
RTS
Reset:
0
0
0
0
0
0
0
0
Figure 21-16. UART Output Port Command Registers (UOP1
n
/UOP0
n
)
Table 21-12. UOP1
n
/UOP0
n
Field Descriptions
Field
Description
7–1
Reserved, must be cleared.
0
RTS
Output port output. Controls assertion (UOP1)/negation (UOP0) of U
n
RTS output.
0 Not affected.
1 Asserts U
n
RTS in UOP1. Negates U
n
RTS in UOP0.