參數(shù)資料
型號(hào): MC68HC908RK2DW
廠商: FREESCALE SEMICONDUCTOR INC
元件分類: 微控制器/微處理器
英文描述: 8-BIT, FLASH, 4 MHz, MICROCONTROLLER, PDSO20
封裝: PLASTIC, SOIC-20
文件頁數(shù): 132/158頁
文件大小: 1020K
代理商: MC68HC908RK2DW
Usage Notes
MC68HC908RK2 Data Sheet, Rev. 5.1
Freescale Semiconductor
75
6.4.7 Improving Settling Time
The settling time of the internal clock generator can be vastly improved if an external clock source can be
used during the settling time. When the internal clock generator is disabled (ICGON is low), the DDIV[3:0]
and DSTG[7:0] bits can be written. Then, when the internal clock generator is re-enabled, the clock period
will automatically start at the point written in the DDIV and DSTG bits.
Since a change in the DDIV and DSTG bits only cause a change in the clock period relative to the starting
point, the starting point must first be captured. The initial clock period can be expressed as in the next
example, where
τX is a process, temperature, and voltage dependent constant and DDIV1 and DSTG1
are the values of DDIV and DSTG when operating at
τ1.
Finding the new values for DDIV and DSTG is easy if the new clock period is a binary multiple or fraction
of the original. In this case, DSTG is unchanged and DDIV2 is DDIV1 + log221).
If the new clock period is not a binary multiple or fraction of the original, both DSTG and DDIV may need
to change according to these equations:
If DSTG2 is greater than 255:
The software required to do this is relatively simple, since most of the math can be done before coding
because the initial and final clock periods are known. An example of how to code this in assembly code
is shown in Figure 6-10. This example is for illustrative purposes only and does not represent a valid
syntax for any particular assembler.
6.4.8 Trimming Frequency on the Internal Clock Generator
The unadjusted frequency of the low-frequency base clock (IBASE), when the comparators in the
frequency comparator indicate zero error, will vary as much as
±25% due to process, temperature, and
voltage dependencies. These dependencies are in the voltage and current references, the offset of the
comparators, and the internal capacitor. The voltage and temperature dependencies have been designed
to be a maximum of approximately
±1% error. The process dependencies account for the rest.
Fortunately, for an individual part, the process dependencies are constant. An individual part can operate
at approximately
±2% variance from its unadjusted operating point over the entire specification range of
the application. If the unadjusted operating point can be changed, the entire variance can be limited
to
±2%.
τ
1
τ
X
2
DDIV1
DSTG1
=
DVFACT
int
τ
2 τ1
()
log
2
()
log
-----------------------------
=
DDIV2
DDIV1
DVFACT
+
=
DSFACT
τ
2 τ1
()
2
DDIV2
DDIV1
()
----------------------------------------------------
=
DSTG2
DSFACT DSTG1
=
DDIV2
1
+
=
DSTG2
2
---------------------
=
相關(guān)PDF資料
PDF描述
MC68HC912BL16CFU8 16-BIT, FLASH, 8 MHz, MICROCONTROLLER, PQFP64
MC68HC916X1CTH16 16-BIT, FLASH, 16.78 MHz, MICROCONTROLLER, PQFP120
MC916X1CTH16B1 16-BIT, FLASH, 16.78 MHz, MICROCONTROLLER, PQFP120
SPMC916X1CTH16 16-BIT, FLASH, 16.78 MHz, MICROCONTROLLER, PQFP120
MC68HCL05J1ADWR2 8-BIT, MROM, 2.1 MHz, MICROCONTROLLER, PDSO20
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC68HC908SR12CB 功能描述:IC MCU 12K FLASH 8MHZ 42-SDIP RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器, 系列:HC08 標(biāo)準(zhǔn)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(shè)備:POR,PWM,溫度傳感器,WDT 輸入/輸出數(shù):21 程序存儲(chǔ)器容量:40KB(20K x 16) 程序存儲(chǔ)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(shù)據(jù)轉(zhuǎn)換器:A/D 6x12b 振蕩器型:內(nèi)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
MC68HC908SR12CFA 功能描述:MICROCONTROLLER 48 PIN RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器, 系列:HC08 其它有關(guān)文件:STM32F101T8 View All Specifications 特色產(chǎn)品:STM32 32-bit Cortex MCUs 標(biāo)準(zhǔn)包裝:490 系列:STM32 F1 核心處理器:ARM? Cortex?-M3 芯體尺寸:32-位 速度:36MHz 連通性:I²C,IrDA,LIN,SPI,UART/USART 外圍設(shè)備:DMA,PDR,POR,PVD,PWM,溫度傳感器,WDT 輸入/輸出數(shù):26 程序存儲(chǔ)器容量:64KB(64K x 8) 程序存儲(chǔ)器類型:閃存 EEPROM 大小:- RAM 容量:10K x 8 電壓 - 電源 (Vcc/Vdd):2 V ~ 3.6 V 數(shù)據(jù)轉(zhuǎn)換器:A/D 10x12b 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 85°C 封裝/外殼:36-VFQFN,36-VFQFPN 包裝:托盤 配用:497-10030-ND - STARTER KIT FOR STM32497-8853-ND - BOARD DEMO STM32 UNIV USB-UUSCIKSDKSTM32-PL-ND - KIT IAR KICKSTART STM32 CORTEXM3497-8512-ND - KIT STARTER FOR STM32F10XE MCU497-8505-ND - KIT STARTER FOR STM32F10XE MCU497-8304-ND - KIT STM32 MOTOR DRIVER BLDC497-6438-ND - BOARD EVALUTION FOR STM32 512K497-6289-ND - KIT PERFORMANCE STICK FOR STM32MCBSTM32UME-ND - BOARD EVAL MCBSTM32 + ULINK-MEMCBSTM32U-ND - BOARD EVAL MCBSTM32 + ULINK2更多... 其它名稱:497-9032STM32F101T8U6-ND
MC68HC912B32CFU8 功能描述:IC MCU 32K FLASH 8MHZ 80-QFP RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器, 系列:HC12 其它有關(guān)文件:STM32F101T8 View All Specifications 特色產(chǎn)品:STM32 32-bit Cortex MCUs 標(biāo)準(zhǔn)包裝:490 系列:STM32 F1 核心處理器:ARM? Cortex?-M3 芯體尺寸:32-位 速度:36MHz 連通性:I²C,IrDA,LIN,SPI,UART/USART 外圍設(shè)備:DMA,PDR,POR,PVD,PWM,溫度傳感器,WDT 輸入/輸出數(shù):26 程序存儲(chǔ)器容量:64KB(64K x 8) 程序存儲(chǔ)器類型:閃存 EEPROM 大小:- RAM 容量:10K x 8 電壓 - 電源 (Vcc/Vdd):2 V ~ 3.6 V 數(shù)據(jù)轉(zhuǎn)換器:A/D 10x12b 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 85°C 封裝/外殼:36-VFQFN,36-VFQFPN 包裝:托盤 配用:497-10030-ND - STARTER KIT FOR STM32497-8853-ND - BOARD DEMO STM32 UNIV USB-UUSCIKSDKSTM32-PL-ND - KIT IAR KICKSTART STM32 CORTEXM3497-8512-ND - KIT STARTER FOR STM32F10XE MCU497-8505-ND - KIT STARTER FOR STM32F10XE MCU497-8304-ND - KIT STM32 MOTOR DRIVER BLDC497-6438-ND - BOARD EVALUTION FOR STM32 512K497-6289-ND - KIT PERFORMANCE STICK FOR STM32MCBSTM32UME-ND - BOARD EVAL MCBSTM32 + ULINK-MEMCBSTM32U-ND - BOARD EVAL MCBSTM32 + ULINK2更多... 其它名稱:497-9032STM32F101T8U6-ND
MC68HC916P1CAA16 功能描述:16位微控制器 - MCU 16B MCU 32K FLASH RoHS:否 制造商:Texas Instruments 核心:RISC 處理器系列:MSP430FR572x 數(shù)據(jù)總線寬度:16 bit 最大時(shí)鐘頻率:24 MHz 程序存儲(chǔ)器大小:8 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:VQFN-40 安裝風(fēng)格:SMD/SMT
MC68HC916P1CFU16 制造商:Rochester Electronics LLC 功能描述:16BIT W/32KB FLASH EEPRO - Bulk