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): 80/130頁
文件大?。?/td> 10504K
代理商: MC68HC705F4FB
MC68HC05F4
6-3
16-BIT PROGRAMMABLE TIMER
6
6.1.1
Counter register and alternate counter register
The double-byte, free-running counter can be read from either of two locations, $0028 – $0029
(counter register) or $002A – $002B (counter alternate register). A read from only the less
signicant byte (LSB) of the free-running counter ($0029 or $002B) receives the count value at the
time of the read. If a read of the free-running counter or alternate counter register rst addresses
the more signicant byte (MSB) ($0028 or $002A), the LSB is transferred to a buffer. This buffer
value remains xed after the rst MSB read, even if the user reads the MSB several times. This
buffer is accessed when reading the free-running counter or alternate counter register LSB and
thus completes a read sequence of the total counter value. In reading either the free-running
counter or alternate counter register, if the MSB is read, the LSB must also be read to complete
the sequence. If the timer overow ag (TOF) is set when the counter register LSB is read then a
read of the timer status register (TSR) will clear the ag.
The counter alternate register differs from the counter register only in that a read of the LSB does
not clear TOF. Therefore, where it is critical to avoid the possibility of missing timer overow
interrupts due to clearing of TOF, the alternate counter register should be used.
The free-running counter is set to $FFFC during power-on and external reset and is always a
read-only register. During a power-on reset, the counter begins running after the oscillator start-up
delay. Because the free-running counter is 16 bits preceded by a xed divide-by-4 prescaler, the
value in the free-running counter repeats every 262,144 internal bus clock cycles. TOF is set when
the counter overows (from $FFFF to $0000); this will cause an interrupt if TOIE is set.
The divide-by-4 prescaler is also reset and the counter resumes normal counting operation. All of
the ags and enable bits remain unaltered by this operation. If access has previously been made
to the high byte of the free-running counter ($0028 or $002A), then the reset counter operation
terminates the access sequence.
Address
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
Timer counter high (CNTH)
$0028
1111 1111
Timer counter low (CNTL)
$0029
1111 1100
Address
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
Alternate counter high (ACNTH)
$002A
1111 1111
Alternate counter low (ACNTL)
$002B
1111 1100
TPG
49
05F4Book Page 3 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
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參數(shù)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 標準包裝: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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