mcf5407 Freescale Semiconductor, Inc, mcf5407 Datasheet - Page 361

• Manufacturer Part Number: mcf5407
• Description: Mcf5407 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

14.3.16 UART Divider Upper/Lower Registers (UDUn/UDLn)
The UDUn registers (formerly called UBG1n) holds the MSB, and the UDLn registers
(formerly UBG2n) hold the LSB of the preload value. UDUn and UDLn concatenate to
provide a divider to CLKIN for transmitter/receiver operation, as described in
Section 14.5.1.2.1, “CLKIN Baud Rates.”
Bits
6–3
Address
Address
7
2
1
0
Reset
Reset
Field
Field
R/W
R/W
COS
—
DB
FFULL/
RxRDY
TxRDY
Name
7
7
Change-of-state. Not used by UART1 in modem mode.
0 UIPCRn[COS] is not selected.
1 Change-of-state occurred on CTS and was programmed in UACRn[IEC] to cause an interrupt.
Reserved, should be cleared.
Delta break. Not used by UART1 in modem mode.
0 No new break-change condition to report. Section 14.3.10, “UART Command Registers (UCRn),”
1 The receiver detected the beginning or end of a received break.
RxRDY (receiver ready) if UMR1n[FFULL/RxRDY] = 0; FIFO full (FFULL) if UMR1n[FFULL/RxRDY]
= 1. Duplicate of USRn[FFULL/RxRDY]. Used by UART1 in modem mode. If FFULL is enabled for
UART0 or UART1, DMA channels 2 or 3 are respectively interrupted when the FIFO is full.
Transmitter ready. This bit is the duplication of USRn[TxRDY]. Used by UART1 in modem mode.
0 The transmitter holding register was loaded by the CPU or the transmitter is disabled. Characters
1 The transmitter holding register is empty and ready to be loaded with a character.
The minimum value that can be loaded on the concatenation of
UDUn with UDLn is 0x0002. Both UDUn and UDLn are
write-only and cannot be read by the CPU.
describes the
loaded into the transmitter holding register when TxRDY = 0 are not sent.
Figure 14-19. UART Divider Upper Register (UDUn)
Figure 14-20. UART Divider Lower Register (UDLn)
Table 14-14. UISRn/UIMRn Field Descriptions
RESET BREAK
Chapter 14. UART Modules
MBAR + 0x1D8 (UDU0), 0x218 (UDU1)
MBAR + 0x1DC (UDL0), 0x21C (UDL1)
-
CHANGE INTERRUPT
NOTE:
Divider MSB
Divider LSB
0000_0000
0000_0000
Description
R/W
R/W
command.
Register Descriptions
0
0
14-19