參數(shù)資料
型號： PIC12LC509AT-04I/MF
廠商： Microchip Technology
文件頁數(shù)： 34/113頁
文件大?。?/td> 0K
描述： IC MCU OTP 1KX12 LV 8-DFN
標(biāo)準(zhǔn)包裝： 3,300
系列： PIC® 12C
核心處理器： PIC
芯體尺寸： 8-位
速度： 4MHz
外圍設(shè)備： POR，WDT
輸入/輸出數(shù)： 5
程序存儲器容量： 1.5KB（1K x 12）
程序存儲器類型： OTP
RAM 容量： 41 x 8
電壓 - 電源 (Vcc/Vdd)： 2.5 V ~ 5.5 V
振蕩器型： 內(nèi)部
工作溫度： -40°C ~ 85°C
封裝/外殼： 8-VDFN 裸露焊盤
包裝： 帶卷 (TR)
其它名稱： PIC12LC509AT04IMF
1999 Microchip Technology Inc.
DS40139E-page 27
PIC12C5XX
6.1
Using Timer0 with an External Clock
When an external clock input is used for Timer0, it
must meet certain requirements. The external clock
requirement is due to internal phase clock (TOSC)
synchronization. Also, there is a delay in the actual
incrementing of Timer0 after synchronization.
6.1.1
EXTERNAL CLOCK SYNCHRONIZATION
When no prescaler is used, the external clock input is
the same as the prescaler output. The synchronization
of
T0CKI
with
the
internal
phase
clocks
is
accomplished by sampling the prescaler output on the
Q2 and Q4 cycles of the internal phase clocks
(Figure 6-4). Therefore, it is necessary for T0CKI to be
high for at least 2TOSC (and a small RC delay of 20 ns)
and low for at least 2TOSC (and a small RC delay of
20 ns). Refer to the electrical specification of the
desired device.
When a prescaler is used, the external clock input is
divided by the asynchronous ripple counter-type
prescaler so that the prescaler output is symmetrical.
For
the
external
clock
to
meet
the
sampling
requirement, the ripple counter must be taken into
account. Therefore, it is necessary for T0CKI to have a
period of at least 4TOSC (and a small RC delay of
40 ns) divided by the prescaler value. The only
requirement on T0CKI high and low time is that they
do not violate the minimum pulse width requirement of
10 ns. Refer to parameters 40, 41 and 42 in the
electrical specification of the desired device.
6.1.2
TIMER0 INCREMENT DELAY
Since the prescaler output is synchronized with the
internal clocks, there is a small delay from the time the
external clock edge occurs to the time the Timer0
module is actually incremented. Figure 6-4 shows the
delay from the external clock edge to the timer
incrementing.
6.1.3
OPTION REGISTER EFFECT ON GP2 TRIS
If the option register is set to read TIMER0 from the pin,
the port is forced to an input regardless of the TRIS reg-
ister setting.
FIGURE 6-4:
TIMER0 TIMING WITH EXTERNAL CLOCK
Increment Timer0 (Q4)
External Clock Input or
Q1
Q2
Q3 Q4
Q1
Q2
Q3 Q4
Q1
Q2
Q3 Q4
Q1
Q2
Q3 Q4
Timer0
T0
T0 + 1
T0 + 2
Small pulse
misses sampling
External Clock/Prescaler
Output After Sampling
(3)
Note 1:
2:
3:
Delay from clock input change to Timer0 increment is 3Tosc to 7Tosc. (Duration of Q = Tosc).
Therefore, the error in measuring the interval between two edges on Timer0 input =
± 4Tosc max.
External clock if no prescaler selected, Prescaler output otherwise.
The arrows indicate the points in time where sampling occurs.
Prescaler Output (2)
(1)
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PIC12LC671-04/P 功能描述:8位微控制器 -MCU 1.75KB 128 RAM 6 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC12LC671-04/SM 功能描述:8位微控制器 -MCU 1.75KB 128 RAM 6 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC12LC671-04I/MF 功能描述:8位微控制器 -MCU 1.75KB 128 RAM 6 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC12LC671-04I/P 功能描述:8位微控制器 -MCU 1.75KB 128 RAM 6 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC12LC671-04I/SM 功能描述:8位微控制器 -MCU 1.75KB 128 RAM 6 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
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