- 您现在的位置：买卖IC网 > PDF目录381506 > AT89LV55-12AC (ATMEL CORP) 8-Bit Microcontroller with 20K Bytes Flash PDF资料下载
参数资料
| 型号： | AT89LV55-12AC |
| 厂商： | ATMEL CORP |
| 元件分类： | 微控制器/微处理器 |
| 英文描述： | 8-Bit Microcontroller with 20K Bytes Flash |
| 中文描述： | 8-BIT, FLASH, 12 MHz, MICROCONTROLLER, PQFP44 |
| 封装： | 10 X 10 MM, 1 MM THICKNESS, 0.80 MM PITCH, PLASTIC, MS-026ACB, TQFP-44 |
| 文件页数： | 11/23页 |
| 文件大小： | 595K |
| 代理商： | AT89LV55-12AC |
AT89LV55
4-203
Programmable Clock Out
A 50% duty cycle clock can be programmed to come out on
P1.0, as shown in Figure 5. This pin, besides being a regu-
lar I/O pin, has two alternate functions. It can be pro-
grammed to input the external clock for Timer/Counter 2 or
to output a 50% duty cycle clock ranging from 61 Hz to 3
MHz at a 12 MHz operating frequency.
To configure the Timer/Counter 2 as a clock generator, bit
C/T2 (T2CON.1) must be cleared and bit T2OE (T2MOD.1)
must be set. Bit TR2 (T2CON.2) starts and stops the timer.
The clock-out frequency depends on the oscillator fre-
quency and the reload value of Timer 2 capture registers
(RCAP2H, TCAP2L), as shown in the following equation:
In the clock-out mode, Timer 2 roll-overs will not generate
an interrupt. This behavior is similar to when Timer 2 is
used as a baud-rate generator. It is possible to use Timer 2
as a baud-rate generator and a clock generator simulta-
neously. Note, however, that the baud-rate and clock-out
frequencies cannot be determined independently from one
another since they both use RCAP2H and RCAP2L.
UART
The UART in the AT89LV55 operates the same way as the
UART in the AT89C51 and AT89C52. For further informa-
tion, see the Microcontroller Data Book, section titled,
“Serial Interface.”
Interrupts
The AT89LV55 has a total of six interrupt vectors: two
external interrupts (INT0 and INT1), three timer interrupts
(Timers 0, 1, and 2), and the serial port interrupt. These
interrupts are all shown in Figure 6.
Each of these interrupt sources can be individually enabled
or disabled by setting or clearing a bit in Special Function
Register IE. IE also contains a global disable bit, EA, which
disables all interrupts at once.
Note that Table 5 shows that bit position IE.6 is unimple-
mented. In the AT89C51 and AT89LV51, bit position IE.5 is
also unimplemented. User software should not write 1s to
these bit positions, since they may be used in future AT89
products.
Timer 2 interrupt is generated by the logical OR of bits TF2
and EXF2 in register T2CON. Neither of these flags is
cleared by hardware when the service routine is vectored
to. In fact, the service routine may have to determine
whether it was TF2 or EXF2 that generated the interrupt,
and that bit will have to be cleared in software.
The Timer 0 and Timer 1 flags, TF0 and TF1, are set at
S5P2 of the cycle in which the timers overflow. The values
are then polled by the circuitry in the next cycle. However,
the Timer 2 flag, TF2, is set at S2P2 and is polled in the
same cycle in which the timer overflows. For further infor-
mation, see the Microcontroller Data Book, section titled
“Interrupts.”
Table 5.
Interrupt Enable (IE) Register
Figure 6.
Interrupt Sources
Clock-Out Frequency
65536
RCAP2H RCAP2L
(
–
4
,
)
[
]
×
-----------------------------------------------------------------------------------------
=
(MSB)
(LSB)
EA
—
ET2
ES
ET1
EX1
ET0
EX0
Enable Bit = 1 enables the interrupt.
Enable Bit = 0 disables the interrupt.
Symbol
Position
Function
EA
IE.7
Disables all interrupts. If EA = 0, no
interrupt is acknowledged. If EA = 1,
each interrupt source is individually
enabled or disabled by setting or
clearing its enable bit.
—
IE.6
Reserved.
ET2
IE.5
Timer 2 interrupt enable bit.
ES
IE.4
Serial Port interrupt enable bit.
ET1
IE.3
Timer 1 interrupt enable bit.
EX1
IE.2
External interrupt 1 enable bit.
ET0
IE.1
Timer 0 interrupt enable bit.
EX0
IE.0
External interrupt 0 enable bit.
User software should never write 1s to unimplemented bits,
because they may be used in future AT89 products.
相关PDF资料 |
PDF描述 |
|---|---|
| AT89LV55-12AI | 8-Bit Microcontroller with 20K Bytes Flash |
| AT89LV55-12JC | 8-Bit Microcontroller with 20K Bytes Flash |
| AT89LV55-12JI | 8-Bit Microcontroller with 20K Bytes Flash |
| AT89LV55-12PC | 8-Bit Microcontroller with 20K Bytes Flash |
| AT89LV55-12PI | High Speed CMOS Logic Hex Inverters 14-TSSOP -55 to 125 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AT89LV55-12AI | 功能描述:8位微控制器 -MCU Microcontroller RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| AT89LV55-12AU | 功能描述:8位微控制器 -MCU 16K FLASH 8051 MCU - 16K FLASH RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| AT89LV5512JC | 制造商:Atmel Corporation 功能描述:MCU 8-bit AT89 80C51 CISC 20KB Flash 3.3V/5V 44-Pin PLCC |
| AT89LV55-12JC | 功能描述:8位微控制器 -MCU 80C31 w/8k RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| AT89LV55-12JI | 功能描述:8位微控制器 -MCU 80C31 w/8k RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
发布紧急采购，3分钟左右您将得到回复。