參數(shù)資料
型號: 935270056518
廠商: NXP SEMICONDUCTORS
元件分類: 微控制器/微處理器
英文描述: 4 CHANNEL(S), 5M bps, SERIAL COMM CONTROLLER, PQCC68
封裝: PLASTIC, MS-018, SOT-188-2, LCC-68
文件頁數(shù): 10/52頁
文件大?。?/td> 680K
代理商: 935270056518
Philips Semiconductors
SC16C754
Quad UART with 64-byte FIFO
Product data
Rev. 02 — 14 March 2003
18 of 49
9397 750 11192
Koninklijke Philips Electronics N.V. 2003. All rights reserved.
6.8 Break and time-out conditions
An RX idle condition is detected when the receiver line, RX, has been HIGH for
4 character time. The receiver line is sampled midway through each bit.
When a break condition occurs, the TX line is pulled LOW. A break condition is
activated by setting LCR[6].
6.9 Programmable baud rate generator
The SC16C754 UART contains a programmable baud generator that takes any clock
input and divides it by a divisor in the range between 1 and (216
1). An additional
divide-by-4 prescaler is also available and can be selected by MCR[7], as shown in
Figure 12. The output frequency of the baud rate generator is 16
× the baud rate. The
formula for the divisor is:
Where:
prescaler = 1, when MCR[7] is set to 0 after reset (divide-by-1 clock selected)
prescaler = 4, when MCR[7] is set to 1 after reset (divide-by-4 clock selected).
Remark: The default value of prescaler after reset is divide-by-1.
Figure 12 shows the internal prescaler and baud rate generator circuitry.
DLL and DLH must be written to in order to program the baud rate. DLL and DLH are
the least signicant and most signicant byte of the baud rate divisor. If DLL and DLH
are both zero, the UART is effectively disabled, as no baud clock will be generated.
Remark: The programmable baud rate generator is provided to select both the
transmit and receive clock rates.
Table 7 and Table 8 show the baud rate and divisor correlation for crystal with
frequency 1.8432 MHz and 3.072 MHz, respectively.
Figure 13 shows the crystal clock circuit reference.
Fig 12. Prescaler and baud rate generator block diagram.
divisor
XTAL1 crystal input frequency
prescaler
---------------------------------------------------------------------------
desired baud rate
16
×
()
---------------------------------------------------------------------------------
=
BAUD RATE
GENERATOR
LOGIC
MCR[7] = 1
MCR[7] = 0
PRESCALER
LOGIC
(DIVIDE-BY-1)
INTERNAL
OSCILLATOR
LOGIC
002aaa233
XTAL1
XTAL2
INPUT CLOCK
PRESCALER
LOGIC
(DIVIDE-BY-4)
REFERENCE
CLOCK
INTERNAL
BAUD RATE
CLOCK FOR
TRANSMITTER
AND
RECEIVER
相關(guān)PDF資料
PDF描述
935270057557 4 CHANNEL(S), 5M bps, SERIAL COMM CONTROLLER, PQFP80
935270056512 4 CHANNEL(S), 5M bps, SERIAL COMM CONTROLLER, PQCC68
935270071112 1 CHANNEL(S), 3M bps, SERIAL COMM CONTROLLER, PDIP40
935270058512 1 CHANNEL(S), 3M bps, SERIAL COMM CONTROLLER, PQCC44
935270058518 1 CHANNEL(S), 3M bps, SERIAL COMM CONTROLLER, PQCC44
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
935270713557 制造商:NXP Semiconductors 功能描述:SUB ONLY IC CHP
935270792551 制造商:NXP Semiconductors 功能描述:IC BUFF DVR TRI-ST 16BIT 56VFBGA
935270792557 制造商:NXP Semiconductors 功能描述:IC BUFF DVR TRI-ST 16BIT 56VFBGA
935270793551 制造商:NXP Semiconductors 功能描述:IC BUS TRCVR 3-ST 16BIT 56VFBGA
935270793557 制造商:NXP Semiconductors 功能描述:IC BUS TRCVR 3-ST 16BIT 56VFBGA