
UART Modules
31-18
Freescale Semiconductor
Using a 80-MHz internal bus clock and letting baud rate equal 9600, then
Eqn. 31-2
Therefore, UBG1
n
equals 0x01 and UBG2
n
equals 0x04.
31.4.1.2.2
External Clock
An external source clock (DT
n
IN) passes through a divide-by-1 or 16 prescaler. If f
extc
is the external clock
frequency, baud rate can be described with this equation:
Eqn. 31-3
31.4.2
Transmitter and Receiver Operating Modes
is a functional block diagram of the transmitter and receiver showing the command and
operating registers, which are described generally in the following sections. For detailed descriptions, refer
to
Section 31.3, “Memory Map/Register Definition
.”
Figure 31-18. Transmitter and Receiver Functional Diagram
31.4.2.1
Transmitter
The transmitter is enabled through the UART command register (UCR
n
). When it is ready to accept a
character, UART sets USR
n
[TXRDY]. The transmitter converts parallel data from the CPU to a serial bit
stream on U
n
TXD. It automatically sends a start bit followed by the programmed number of data bits, an
Divider
80
MHz
32 x 9600
[
]
-------------------------------
260 decimal
(
)
0x
0104 hexadecimal
(
)
=
=
=
Baudrate
f
extc
(16 or 1)
---------------------
=
Receiver Shift Register
UART Command Register (UCRn)
W
UART Status Register (USRn)
R
Transmitter Shift Register
UART Mode Register 1 (UMR1n)
R/W
UART Mode Register 2 (UMR2n)
R/W
Transmitter Holding Register
W
Receiver Holding Register 3
Receiver Holding Register 2
Receiver Holding Register 1
R
UART Receive
UART
Buffer (URBn)
(4 Registers)
UARTn
External
Interface
Transmit Buffer
(UTBn)
(2 Registers)
FIFO
UnRXD
UnTXD
MCF5329 Reference Manual, Rev 3
Содержание MCF5329
Страница 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 126: ...Enhanced Multiply Accumulate Unit EMAC 4 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 564: ...Liquid Crystal Display Controller LCDC 22 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 692: ...Programmable Interrupt Timers PIT0 PIT3 28 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 720: ...Queued Serial Peripheral Interface QSPI 30 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 790: ...Message Digest Hardware Accelerator MDHA 33 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 902: ...Register Memory Map Quick Reference A 26 Freescale Semiconductor MCF5329 Reference Manual Rev 3...