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参数资料
型号： ST10F269Z2Q3
厂商： STMICROELECTRONICS
元件分类： 微控制器/微处理器
英文描述： 16-BIT, FLASH, 40 MHz, MICROCONTROLLER, PQFP144
封装： 28 X 28 MM, PLASTIC, QFP-144
文件页数： 88/160页
文件大小： 1541K
代理商： ST10F269Z2Q3
ST10F269
33/160
5.6.5 - Choosing the Baud Rate for the BSL
The calculation of the serial Baud rate for ASC0
from the length of the first zero Byte that is
received, allows the operation of the bootstrap
loader of the ST10F269 with a wide range of Baud
rates. However, the upper and lower limits have to
be kept, in order to insure proper data transfer.
The ST10F269 uses timer T6 to measure the
length of the initial zero Byte. The quantization
uncertainty of this measurement implies the first
deviation from the real Baud rate, the next
deviation is implied by the computation of the
S0BRL reload value from the timer contents. The
formula below shows the association:
For a correct data transfer from the host to the
ST10F269 the maximum deviation between the
internal initialized Baud rate for ASC0 and the real
Baud rate of the host should be below 2.5%. The
deviation (FB, in percent) between host Baud rate
and ST10F269 Baud rate can be calculated via
the formula below:
Note: Function (FB) does not consider the
tolerances of oscillators and other devices
supporting the serial communication.
This Baud rate deviation is a nonlinear function
depending on the CPU clock and the Baud rate of
the host. The maxima of the function (FB)
increase with the host Baud rate due to the
smaller Baud rate pre-scaler factors and the
implied higher quantization error (see Figure 8).
The minimum Baud rate (BLow in the Figure 8) is
determined by the maximum count capacity of
timer T6, when measuring the zero Byte, and it
depends on the CPU clock. Using the maximum
T6 count 2
16 in the formula the minimum Baud
rate can be calculated. The lowest standard Baud
rate in this case would be 1200 Baud. Baud rates
below BLow would cause T6 to overflow. In this
case ASC0 cannot be initialized properly.
The maximum Baud rate (BHigh in the Figure 8)
is the highest Baud rate where the deviation still
does not exceed the limit, so all Baud rates
between BLow and BHigh are below the deviation
limit. The maximum standard Baud rate that fulfills
this requirement is 19200 Baud.
Higher Baud rates, however, may be used as
long as the actual deviation does not exceed the
limit. A certain Baud rate (marked ’I’ in Figure 8)
may violate the deviation limit, while an even
higher Baud rate (marked ’II’ in Figure 8) stays
very well below it. This depends on the host
interface.
f
CPU
32
S0BRL
1
+
()
×
------------------------------------------------
BST10F269 =
S0BRL
T6
36
–
72
--------------------
=
T6
9
4
---
f
CPU
B
Host
-----------------
×
=
,
F
B
C ontr
B
Ho st
–
B
C ontr
--------------------------------------------
100
×
=
% ,
F
B
2.5
≤
%
Figure 8 : Baud Rate Deviation Between Host and ST10F269
BLow
2.5%
FB
BHigh
I
II
BHOST
相关PDF资料
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相关代理商/技术参数
参数描述
ST10F269Z2Q6 功能描述:16位微控制器 - MCU 256K Flash 12K RAM RoHS:否 制造商:Texas Instruments 核心:RISC 处理器系列:MSP430FR572x 数据总线宽度:16 bit 最大时钟频率:24 MHz 程序存储器大小:8 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:2 V to 3.6 V 工作温度范围:- 40 C to + 85 C 封装 / 箱体:VQFN-40 安装风格:SMD/SMT
ST10F269Z2Q6/TR 功能描述:16位微控制器 - MCU 16B MCU 256K Byte and 12K Byte RAM RoHS:否 制造商:Texas Instruments 核心:RISC 处理器系列:MSP430FR572x 数据总线宽度:16 bit 最大时钟频率:24 MHz 程序存储器大小:8 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:2 V to 3.6 V 工作温度范围:- 40 C to + 85 C 封装 / 箱体:VQFN-40 安装风格:SMD/SMT
ST10F269Z2QX 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:16-BIT MCU WITH MAC UNIT, 256K BYTE FLASH MEMORY AND 12K BYTE RAM
ST10F269Z2T3 功能描述:16位微控制器 - MCU ST10F272 16B MCU RoHS:否 制造商:Texas Instruments 核心:RISC 处理器系列:MSP430FR572x 数据总线宽度:16 bit 最大时钟频率:24 MHz 程序存储器大小:8 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:2 V to 3.6 V 工作温度范围:- 40 C to + 85 C 封装 / 箱体:VQFN-40 安装风格:SMD/SMT
ST10F269Z2T6 功能描述:16位微控制器 - MCU ST10F272 16B MCU RoHS:否 制造商:Texas Instruments 核心:RISC 处理器系列:MSP430FR572x 数据总线宽度:16 bit 最大时钟频率:24 MHz 程序存储器大小:8 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:2 V to 3.6 V 工作温度范围:- 40 C to + 85 C 封装 / 箱体:VQFN-40 安装风格:SMD/SMT
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