參數資料
型號: ADUC834BCPZ-REEL
廠商: Analog Devices Inc
文件頁數: 57/80頁
文件大?。?/td> 0K
描述: IC MCU 62K FLASH ADC/DAC 56LFCSP
標準包裝: 2,500
系列: MicroConverter® ADuC8xx
核心處理器: 8052
芯體尺寸: 8-位
速度: 12.58MHz
連通性: EBI/EMI,I²C,SPI,UART/USART
外圍設備: POR,PSM,PWM,溫度傳感器,WDT
輸入/輸出數: 34
程序存儲器容量: 62KB(62K x 8)
程序存儲器類型: 閃存
EEPROM 大?。?/td> 4K x 8
RAM 容量: 2.25K x 8
電壓 - 電源 (Vcc/Vdd): 2.7 V ~ 5.25 V
數據轉換器: A/D 3x16b,4x24b; D/A 1x12b
振蕩器型: 內部
工作溫度: -40°C ~ 85°C
封裝/外殼: 56-VFQFN 裸露焊盤,CSP
包裝: 帶卷 (TR)
REV. A
–60–
ADuC834
BAUD RATE GENERATION USING TIMER 3
The high integer dividers in a UART block means that high
speed baud rates are not always possible using some particular
crystals. e.g., using a 12 MHz crystal, a baud rate of 115200 is
not possible. To address this problem the ADuC834 has added
a dedicated baud rate timer (Timer 3) specifically for generating
highly accurate baud rates.
Timer 3 can be used instead of Timer 1 or Timer 2 for generating
very accurate high speed UART baud rates including 115200
and 230400. Timer 3 also allows a much wider range of baud
rates to be obtained. In fact, every desired bit rate from 12 bits
to 393216 bits can be generated to within an error of
± 0.8%.
Timer 3 also frees up the other three timers allowing them to be
used for different applications. A block diagram of Timer 3 is
shown in Figure 57.
(1 + T3FD/64)
2
T3 RX/TX
CLOCK
CORE
CLK*
T3EN
RX
CLOCK
TX CLOCK
TIMER 1/TIMER 2
RX CLOCK (FIG 56)
FRACTIONAL
DIVIDER
0
1
TIMER 1/TIMER 2
TX CLOCK (FIG 56)
16
2DIV
*THE CORE CLOCK IS THE OUTPUT OF THE PLL (SEE "ON-CHIP PLL")
Figure 57. Timer 3, UART Baud Rates
Two SFRs (T3CON and T3FD) are used to control Timer 3.
T3CON is the baud rate control SFR, allowing Timer 3 to be
used to set up the UART baud rate, and setting up the binary
divider (DIV).
Table XXXIII. T3CON SFR Bit Designations
Bit
Name
Description
7
T3EN
Set to enable Timer 3 to generate the baud
rate. When set PCON.7, T2CON.4 and
T2CON.5 are ignored. Cleared to let the baud
rate be generated as per a standard 8052.
6
–––
Reserved for future use
5
–––
Reserved for future use
4
–––
Reserved for future use
3
–––
Reserved for future use
2
DIV2
Binary Divider Factor
1
DIV1
DIV2
DIV1
DIV0
Bin Divider
0
DIV0
0
1
00
1
2
01
0
4
01
1
8
10
0
16
10
1
32
11
0
64
11
1
128
The appropriate value to write to the DIV2-1-0 bits can be
calculated using the following formula where fCORE is the output
of the PLL as described in the “On-Chip PLL” description.
Note: The DIV value must be rounded down.
DIV
f
Baud Rate
CORE
=
×
()
log
32
2
T3FD is the fractional divider ratio required to achieve the
required baud rate. We can calculate the appropriate value for
T3FD using the following formula.
Note: T3FD should be rounded to the nearest integer.
TFD
f
Baud Rate
CORE
DIV
3
2
64
=
×
Once the values for DIV and T3FD are calculated, the actual
baud rate can be calculated using the following formula:
Actual Baud Rate
f
TFD
CORE
DIV
=
×
×+
()
2
23
64
For a baud rate of 115200 while operating from the maximum
core frequency (CD = 0) we have:
DIV
TFD
Dh
()
==
()
×
() ==
log
/
/ log
.
..
12582912 32
115200
2
1 77
1
32
12 582912
2
115200
64
45 22
2
1
Therefore, the actual baud rate is 115439 bits.
Table XXXIV. Commonly Used Baud Rates Using Timer 3
Ideal
%
Baud
CD
DIV
T3CON
T3FD
Error
230400
0
80H
2DH
0.2
115200
0
1
81H
2DH
0.2
115200
1
0
80H
2DH
0.2
57600
0
2
82H
2DH
0.2
57600
1
81H
2DH
0.2
57600
2
0
80H
2DH
0.2
38400
0
3
83H
12H
0.1
38400
1
2
82H
12H
0.1
38400
2
1
81H
12H
0.1
38400
3
0
80H
12H
0.1
19200
0
4
84H
12H
0.1
19200
1
3
83H
12H
0.1
19200
2
82H
12H
0.1
19200
3
1
81H
12H
0.1
19200
4
0
80H
12H
0.1
9600
0
5
85H
12H
0.1
9600
1
4
84H
12H
0.1
9600
2
3
83H
12H
0.1
9600
3
2
82H
12H
0.1
9600
4
1
81H
12H
0.1
9600
5
0
80H
12H
0.1
38400
0
3
83H
12H
0.1
相關PDF資料
PDF描述
ADUC836BCPZ IC MCU 62K FLASH ADC/DAC 56LFCSP
ADUC843BSZ62-5 IC ADC 12BIT W/FLASH MCU 52-MQFP
ADUC845BCPZ62-5 IC FLASH MCU W/24BIT ADC 56-CSP
ADUC847BCPZ62-5 IC MCU FLASH W/24BIT ADC 56-CSP
ADV202BBCZ-135 IC CODEC VIDEO 135MHZ 144CSPBGA
相關代理商/技術參數
參數描述
ADUC834BS 制造商:Analog Devices 功能描述:MCU 8-bit ADuC8xx 8052 CISC 62KB Flash 3.3V/5V 52-Pin MQFP 制造商:Rochester Electronics LLC 功能描述:8BIT CISC 62KB FLASH 12.58MHZ 3.3/5V 52MQFP - Bulk 制造商:Analog Devices 功能描述:8BIT MCU +24/16BIT ADC SMD MQFP52
ADUC834BSZ 功能描述:IC ADC DUAL16/24BIT W/MCU 52MQFP RoHS:是 類別:集成電路 (IC) >> 嵌入式 - 微控制器, 系列:MicroConverter® ADuC8xx 標準包裝:250 系列:56F8xxx 核心處理器:56800E 芯體尺寸:16-位 速度:60MHz 連通性:CAN,SCI,SPI 外圍設備:POR,PWM,溫度傳感器,WDT 輸入/輸出數:21 程序存儲器容量:40KB(20K x 16) 程序存儲器類型:閃存 EEPROM 大小:- RAM 容量:6K x 16 電壓 - 電源 (Vcc/Vdd):2.25 V ~ 3.6 V 數據轉換器:A/D 6x12b 振蕩器型:內部 工作溫度:-40°C ~ 125°C 封裝/外殼:48-LQFP 包裝:托盤 配用:MC56F8323EVME-ND - BOARD EVALUATION MC56F8323
ADUC836 制造商:AD 制造商全稱:Analog Devices 功能描述:MicroConverter, Dual 16-Bit-ADCs with Embedded 62 kB Flash MCU
ADUC836_02 制造商:AD 制造商全稱:Analog Devices 功能描述:MicroConverter, Dual 16-Bit ADCs with Embedded 62 kB Flash MCU
ADUC836BCP 制造商:Rochester Electronics LLC 功能描述: 制造商:Analog Devices 功能描述: