- 您现在的位置：买卖IC网 > PDF目录132964 > MR83C154DTXXX-25P883 (ATMEL CORP) 8-BIT, MROM, 25 MHz, MICROCONTROLLER, CQCC44 PDF资料下载
参数资料
| 型号： | MR83C154DTXXX-25P883 |
| 厂商： | ATMEL CORP |
| 元件分类： | 微控制器/微处理器 |
| 英文描述： | 8-BIT, MROM, 25 MHz, MICROCONTROLLER, CQCC44 |
| 封装： | LCC-44 |
| 文件页数： | 14/298页 |
| 文件大小： | 8529K |
| 代理商： | MR83C154DTXXX-25P883 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页当前第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页第81页第82页第83页第84页第85页第86页第87页第88页第89页第90页第91页第92页第93页第94页第95页第96页第97页第98页第99页第100页第101页第102页第103页第104页第105页第106页第107页第108页第109页第110页第111页第112页第113页第114页第115页第116页第117页第118页第119页第120页第121页第122页第123页第124页第125页第126页第127页第128页第129页第130页第131页第132页第133页第134页第135页第136页第137页第138页第139页第140页第141页第142页第143页第144页第145页第146页第147页第148页第149页第150页第151页第152页第153页第154页第155页第156页第157页第158页第159页第160页第161页第162页第163页第164页第165页第166页第167页第168页第169页第170页第171页第172页第173页第174页第175页第176页第177页第178页第179页第180页第181页第182页第183页第184页第185页第186页第187页第188页第189页第190页第191页第192页第193页第194页第195页第196页第197页第198页第199页第200页第201页第202页第203页第204页第205页第206页第207页第208页第209页第210页第211页第212页第213页第214页第215页第216页第217页第218页第219页第220页第221页第222页第223页第224页第225页第226页第227页第228页第229页第230页第231页第232页第233页第234页第235页第236页第237页第238页第239页第240页第241页第242页第243页第244页第245页第246页第247页第248页第249页第250页第251页第252页第253页第254页第255页第256页第257页第258页第259页第260页第261页第262页第263页第264页第265页第266页第267页第268页第269页第270页第271页第272页第273页第274页第275页第276页第277页第278页第279页第280页第281页第282页第283页第284页第285页第286页第287页第288页第289页第290页第291页第292页第293页第294页第295页第296页第297页第298页
110
ATmega8A [DATASHEET]
8159E–AVR–02/2013
The Oscillator is optimized for use with a 32.768 kHz watch crystal. Applying an external clock to the TOSC1 pin
may result in incorrect Timer/Counter2 operation. The CPU main clock frequency must be more than four times
the Oscillator frequency.
When writing to one of the registers TCNT2, OCR2, or TCCR2, the value is transferred to a temporary register,
and latched after two positive edges on TOSC1. The user should not write a new value before the contents of
the temporary register have been transferred to its destination. Each of the three mentioned registers have their
individual temporary register, which means that e.g. writing to TCNT2 does not disturb an OCR2 write in
progress. To detect that a transfer to the destination register has taken place, the Asynchronous Status Register
– ASSR has been implemented.
When entering Power-save mode after having written to TCNT2, OCR2, or TCCR2, the user must wait until the
written register has been updated if Timer/Counter2 is used to wake up the device. Otherwise, the MCU will
enter sleep mode before the changes are effective. This is particularly important if the Output Compare2
interrupt is used to wake up the device, since the Output Compare function is disabled during writing to OCR2
or TCNT2. If the write cycle is not finished, and the MCU enters sleep mode before the OCR2UB bit returns to
zero, the device will never receive a Compare Match interrupt, and the MCU will not wake up.
If Timer/Counter2 is used to wake the device up from Power-save mode, precautions must be taken if the user
wants to re-enter one of these modes: The interrupt logic needs one TOSC1 cycle to be reset. If the time
between wake-up and re-entering sleep mode is less than one TOSC1 cycle, the interrupt will not occur, and the
device will fail to wake up. If the user is in doubt whether the time before re-entering Power-save or Extended
Standby mode is sufficient, the following algorithm can be used to ensure that one TOSC1 cycle has elapsed:
1.
Write a value to TCCR2, TCNT2, or OCR2.
2.
Wait until the corresponding Update Busy Flag in ASSR returns to zero.
3.
Enter Power-save or Extended Standby mode.
When the asynchronous operation is selected, the 32.768kHz Oscillator for Timer/Counter2 is always running,
except in Power-down and Standby modes. After a Power-up Reset or Wake-up from Power-down or Standby
mode, the user should be aware of the fact that this Oscillator might take as long as one second to stabilize. The
user is advised to wait for at least one second before using Timer/Counter2 after Power-up or Wake-up from
Power-down or Standby mode. The contents of all Timer/Counter2 Registers must be considered lost after a
wake-up from Power-down or Standby mode due to unstable clock signal upon start-up, no matter whether the
Oscillator is in use or a clock signal is applied to the TOSC1 pin.
Description of wake up from Power-save or Extended Standby mode when the timer is clocked asynchronously:
When the interrupt condition is met, the wake up process is started on the following cycle of the timer clock, that
is, the timer is always advanced by at least one before the processor can read the counter value. After wake-up,
the MCU is halted for four cycles, it executes the interrupt routine, and resumes execution from the instruction
following SLEEP.
Reading of the TCNT2 Register shortly after wake-up from Power-save may give an incorrect result. Since
TCNT2 is clocked on the asynchronous TOSC clock, reading TCNT2 must be done through a register
synchronized to the internal I/O clock domain. Synchronization takes place for every rising TOSC1 edge. When
waking up from Power-save mode, and the I/O clock (clk
I/O) again becomes active, TCNT2 will read as the
previous value (before entering sleep) until the next rising TOSC1 edge. The phase of the TOSC clock after
waking up from Power-save mode is essentially unpredictable, as it depends on the wake-up time. The
recommended procedure for reading TCNT2 is thus as follows:
1.
Write any value to either of the registers OCR2 or TCCR2.
2.
Wait for the corresponding Update Busy Flag to be cleared.
3.
Read TCNT2.
During asynchronous operation, the synchronization of the Interrupt Flags for the asynchronous timer takes
three processor cycles plus one timer cycle. The timer is therefore advanced by at least one before the
相关PDF资料 |
PDF描述 |
|---|---|
| MR83C154DTXXX-16/883 | 8-BIT, MROM, 16 MHz, MICROCONTROLLER, CQCC44 |
| MQ83C154DTXXX-25P883D | 8-BIT, MROM, 25 MHz, MICROCONTROLLER, CQFP44 |
| MD80C52XXX-36/883 | 8-BIT, MROM, 36 MHz, MICROCONTROLLER, CDIP40 |
| M34507M2-XXXFP | 4-BIT, MROM, 4.4 MHz, MICROCONTROLLER, PDSO24 |
| M48T08Y-10MH1TR | 0 TIMER(S), REAL TIME CLOCK, PDSO28 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MR83C154-L16 | 制造商:TEMIC 制造商全称:TEMIC Semiconductors 功能描述:CMOS 0 to 36 MHz Single Chip 8-bit Microcontroller |
| MR83C154T-12 | 制造商:TEMIC 制造商全称:TEMIC Semiconductors 功能描述:CMOS 0 to 36 MHz Single Chip 8-bit Microcontroller |
| MR83C154T-16 | 制造商:TEMIC 制造商全称:TEMIC Semiconductors 功能描述:CMOS 0 to 36 MHz Single Chip 8-bit Microcontroller |
| MR83C154T-20 | 制造商:TEMIC 制造商全称:TEMIC Semiconductors 功能描述:CMOS 0 to 36 MHz Single Chip 8-bit Microcontroller |
| MR83C154T-25 | 制造商:TEMIC 制造商全称:TEMIC Semiconductors 功能描述:CMOS 0 to 36 MHz Single Chip 8-bit Microcontroller |
发布紧急采购，3分钟左右您将得到回复。