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UART Modules
MCF5272 ColdFire
®
Integrated Microprocessor User’s Manual, Rev. 3
Freescale Semiconductor
16-15
16.3.13 UART Transmitter FIFO Registers (UTF
n
)
The UTF
n
registers contain control and status bits for the transmitter FIFO. Note that some bits are
read-only.
describes UTF
n
fields.
7
6
5
4
0
Field
TXS
FULL
TXB
Reset
1100_0000
R/W
R/W
R
R
Address
MBAR + 0x128 (UTF0), 0x168 (UTF1)
Figure 16-16. UART Transmitter FIFO Registers (UTF
n
)
Table 16-10. UTF
n
Field Descriptions
Bits
Name
Description
7–6
TXS
Transmitter status. When written to, these bits control the meaning of UISR
n
[TxFIFO].
00 Inhibit transmitter FIFO status indication in UISR
n
.
01 Transmitter FIFO Š 25% empty
10 Transmitter FIFO Š 50% empty
11 Transmitter FIFO Š 75% empty
When read, these bits indicate the emptiness level of the FIFO.
00 Transmitter FIFO < 25% empty
01 Transmitter FIFO Š 25% empty
10 Transmitter FIFO Š 50% empty
11 Transmitter FIFO Š 75% empty
5
FULL
Transmitter FIFO full.
0 Transmitter FIFO is not full and can be loaded with a character.
1 Transmitter FIFO is full. Characters loaded into the transmitter FIFO when it is full are not transmitted.
4–0
TXB
Transmitter buffer data level. Indicates the number of bytes, between 0 and 24, stored in the transmitter FIFO.