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PIC12C508A-04/P 参数 Datasheet PDF下载

PIC12C508A-04/P图片预览
型号: PIC12C508A-04/P
PDF下载: 下载PDF文件 查看货源
内容描述: 8引脚, 8位CMOS微控制器 [8-Pin, 8-Bit CMOS Microcontrollers]
分类和应用: 微控制器和处理器外围集成电路光电二极管PC可编程只读存储器时钟
文件页数/大小: 113 页 / 1604 K
品牌: MICROCHIP [ MICROCHIP ]
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PIC12C5XX  
8.7  
Time-Out Sequence, Power Down,  
and Wake-up from SLEEP Status Bits  
(TO/PD/GPWUF)  
FIGURE 8-14: BROWN-OUT PROTECTION  
CIRCUIT 2  
VDD  
The TO, PD, and GPWUF bits in the STATUS register  
can be tested to determine if a RESET condition has  
been caused by a power-up condition, a MCLR or  
Watchdog Timer (WDT) reset.  
VDD  
VDD  
R1  
Q1  
MCLR  
TABLE 8-7:  
TO/PD/GPWUF STATUS  
AFTER RESET  
R2  
40k*  
PIC12C5XX  
GPWUF TO PD  
RESET caused by  
WDT wake-up from  
0
0
0
0
0
1
0
u
0
SLEEP  
WDT time-out (not from  
SLEEP)  
This brown-out circuit is less expensive, although  
less accurate. Transistor Q1 turns off when VDD  
is below a certain level such that:  
MCLR wake-up from  
SLEEP  
R1  
= 0.7V  
0
0
1
1
u
1
1
u
0
Power-up  
VDD •  
R1 + R2  
MCLR not during SLEEP  
*Refer to Figure 8-7 and Table 11-1 for internal  
weak pull-up on MCLR.  
Wake-up from SLEEP on  
pin change  
Legend: u = unchanged  
Note 1: The TO, PD, and GPWUF bits maintain  
their status (u) until a reset occurs. A low-  
pulse on the MCLR input does not change  
the TO, PD, and GPWUF status bits.  
FIGURE 8-15: BROWN-OUT PROTECTION  
CIRCUIT 3  
VDD  
8.8  
Reset on Brown-Out  
MCP809  
VDD  
bypass  
capacitor  
Vss  
A brown-out is a condition where device power (VDD)  
dips below its minimum value, but not to zero, and then  
recovers. The device should be reset in the event of a  
brown-out.  
VDD  
RST  
MCLR  
PIC12C5XX  
To reset PIC12C5XX devices when  
a brown-out  
occurs, external brown-out protection circuits may be  
This brown-out protection circuit employs  
Microchip Technology’s MCP809 microcontroller  
supervisor. The MCP8XX and MCP1XX family of  
supervisors provide push-pull and open collector  
outputs with both high and low active reset pins.  
There are 7 different trip point selections to  
accomodate 5V and 3V systems.  
built, as shown in Figure 8-13  
Figure 8-15  
, Figure 8-14 and  
FIGURE 8-13: BROWN-OUT PROTECTION  
CIRCUIT 1  
VDD  
VDD  
VDD  
33k  
Q1  
10k  
MCLR  
40k*  
PIC12C5XX  
This circuit will activate reset when VDD goes below  
Vz + 0.7V (where Vz = Zener voltage).  
*Refer to Figure 8-7 and Table 11-1 for internal  
weak pull-up on MCLR.  
DS40139E-page 44  
1999 Microchip Technology Inc.  
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