參數(shù)資料
型號: MC68HC705F4FB
廠商: FREESCALE SEMICONDUCTOR INC
元件分類: 微控制器/微處理器
英文描述: 8-BIT, OTPROM, 1.789 MHz, MICROCONTROLLER, PQFP44
封裝: PLASTIC, QFP-44
文件頁數(shù): 72/130頁
文件大?。?/td> 10504K
代理商: MC68HC705F4FB
5-2
MC68HC05F4
CORE TIMER
5
As shown in Figure 5-1, the timer is driven by the internal bus clock divided by four with a xed
prescaler. This signal drives an 8-bit ripple counter. The value of this 8-bit ripple counter can be
read by the CPU at any time, by accessing the CTIMER counter register (CTCR) at address $09.
A timer overow function is implemented on the last stage of this counter, giving a possible
interrupt at the rate of fOP/1024. (The POR signal (tPORL) is also derived from this register, at
fOP/4064.) The counter register circuit is followed by four more stages, with the resulting clock
(fOP/16384) driving the real time interrupt circuit. The RTI circuit consists of three divider stages
with a 1-of-4 selector. The output of the RTI circuit is further divided by 8 to drive the COP
watchdog timer circuit. The RTI rate selector bits, and the RTI and CTIMER overow enable bits
and ags, are located in the CTIMER control and status register (CTCSR) at location $08.
CTOF (core timer overow ag) is a clearable, read-only status bit and is set when the 8-bit ripple
counter rolls over from $FF to $00. A CPU interrupt request will be generated if CTOFE is set.
Clearing the CTOF is done by writing a ‘0’ to it. Writing a ‘1’ to CTOF has no effect on the bit’s
value. Reset clears CTOF.
When CTOFE (core timer overow enable) is set, a CPU interrupt request is generated when the
CTOF bit is set. Reset clears CTOFE.
The core timer counter register (CTCR) is a read-only register that contains the current value of
the 8-bit ripple counter at the beginning of the timer chain. This counter is clocked at fOP/4 and can
be used for various functions including a software input capture. Extended time periods can be
attained using the CTIMER overow function to increment a temporary RAM storage location
thereby simulating a 16-bit (or more) counter.
The power-on cycle clears the entire counter chain and begins clocking the counter. After tPORL
cycles, the power-on reset circuit is released, which again clears the counter chain and allows the
device to come out of reset. At this point, if RESET is not asserted, the timer will start counting up
from zero and normal device operation will begin. When RESET is asserted at any time during
operation (other than POR), the counter chain will be cleared.
5.1
Real time interrupts (RTI)
The real time interrupt circuit consists of a three stage divider and a 1-of-4 selector. The clock
frequency that drives the RTI circuit is fOP/2
14 (or f
OP/16 384), with three additional divider stages,
giving a maximum interrupt period of 4 seconds at a bus frequency (fOP) of 32kHz. Register details
are given in Section 5.2.
TPG
42
05F4Book Page 2 Tuesday, August 5, 1997 1:10 pm
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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相關(guān)PDF資料
PDF描述
MC68HC05F4FB 8-BIT, MROM, 1.789 MHz, MICROCONTROLLER, PQFP44
MC68HC05F4CDW 8-BIT, MROM, 1.789 MHz, MICROCONTROLLER, PDSO28
MC68HC705G4 8-BIT, OTPROM, 1 MHz, MICROCONTROLLER, PQFP80
MC68HC05G3 8-BIT, OTPROM, 2 MHz, MICROCONTROLLER, PQFP80
MC68HC705J5ACJP 8-BIT, OTPROM, 2.1 MHz, MICROCONTROLLER, PDIP16
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC68HC705G1B 制造商:Rochester Electronics LLC 功能描述:- Bulk
MC68HC705J1A 制造商:Freescale Semiconductor 功能描述:
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MC68HC705J1ACP 功能描述:IC MCU 4MHZ 1.2K OTP 20-DIP RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器, 系列:HC05 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 程序存儲器容量:64KB(64K x 8) 程序存儲器類型: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
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