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參數(shù)資料
| 型號： | PCD3745AP |
| 廠商： | NXP SEMICONDUCTORS |
| 元件分類： | 微控制器/微處理器 |
| 英文描述： | 8-bit microcontroller with 4.5 kbytes OTP memory and 32 kHz real-time clock |
| 中文描述： | 8-BIT, OTPROM, 16 MHz, MICROCONTROLLER, PDIP28 |
| 文件頁數(shù)： | 7/32頁 |
| 文件大?。?/td> | 156K |
| 代理商： | PCD3745AP |
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1999 Feb 02
7
Philips Semiconductors
Product specification
8-bit microcontroller with 4.5 kbytes OTP
memory and 32 kHz real-time clock
PCD3745A
6
REAL-TIME CLOCK (RTC)
The RTC consists of a 32 kHz crystal oscillator, a 32 kHz
to 1 second, 1.5 second and 1 minute divider chain, an
8-bit Frequency Adjustment Register (FAR) and the Clock
Control Register (CLCR). The complete real-time clock
section is independent of the microcontroller status, even
in Idle or Stop mode.
6.1
Oscillator
The internal 32 kHz oscillator requires an external
32.768 kHz quartz crystal (a positive deviation up to
+259 ppm is allowed by using frequency adjustment) and
an external feedback resistor (4.7 M
) connected
between the RTC1 and RTC2 pins. The oscillator is
controlled by the RUN bit in the Clock Control Register.
6.2
Divider chain
The divider chain operates with the 32 kHz oscillator
output and divides this signal down to produce three
different clocks with periods of 1 second, 1.5 second and
1 minute. Depending on the state of the ITS and SITS bits
in the Clock Control Register, the falling edge of the
1 second, 1.5 second or 1 minute clock is used to set the
Clock Interrupt Flag (CIF) in the Clock Control Register.
Since the clock interrupt is used to let the microcontroller
leave the Stop mode, it is wire ORed with the external
interrupt (CE/T0) and has the same functionality, e.g. it
must be enabled in the Clock Control Register (ECI = 1)
and by execution of EN I. The clock interrupt will then be
treated as an external interrupt
Additionally, the divider chain generates a 16 kHz clock
(RCO) that can be routed through port line P1.7/RCO,
controlled by the ERCO bit in the Clock Control Register.
6.3
Frequency adjustment
Frequency adjustment is used to extend the interrupt time
by defining the number of 16 kHz clocks in the Frequency
Adjustment Register that will be counted twice within the
first 1 second or 1.5 second period after a minute interrupt.
The DIV512 is reset if its contents is equal to FAR, this will
extend the time of the next interrupt. This is done within the
first 1 second or 1.5 seconds of every minute. If the second
interrupt is used (ITS = 1 and SITS = 0), every 60th
interval may be up to 15.3 ms longer than the others as a
result of the frequency adjustment. If the 1.5 second
interrupt is used (ITS = 1 and SITS = 1), the prolongation
will affect every 40th interval. The adjusted Minute
Interrupt Time (MIT) shows now a maximum deviation of
0.5 ppm.
The frequency adjustment value of the real-time clock
section is defined by the decimal value of the contents of
the 8-bit Frequency Adjustment Register. It can be read or
written. The significance of the individual bits is illustrated
by the following equation:
Table 7 shows the recommended correction factor FAR for
all allowed real-time clock frequencies (FRCO).
The value of CLCR and FAR at reset is 00H.
Minute Interrupt Time (MIT)
60
2
FRCO
2
14
FAR
+
×
=
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PDF描述 |
|---|---|
| PCD3745AT | 8-bit microcontroller with 4.5 kbytes OTP memory and 32 kHz real-time clock |
| PCD3755A | 8-bit microcontrollers with DTMF generator, 8 kbytes OTP and 128 bytes EEPROM |
| PCD3755AH | 8-bit microcontrollers with DTMF generator, 8 kbytes OTP and 128 bytes EEPROM |
| PCD3755AP | 8-bit microcontrollers with DTMF generator, 8 kbytes OTP and 128 bytes EEPROM |
| PCD3755AT | 8-bit microcontrollers with DTMF generator, 8 kbytes OTP and 128 bytes EEPROM |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| PCD3745AT | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:8-bit microcontroller with 4.5 kbytes OTP memory and 32 kHz real-time clock |
| PCD3745ATD-T | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:8-Bit Microcontroller |
| PCD3755A | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:8-bit microcontrollers with DTMF generator, 8 kbytes OTP and 128 bytes EEPROM |
| PCD3755AH | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:8-bit microcontrollers with DTMF generator, 8 kbytes OTP and 128 bytes EEPROM |
| PCD3755AP | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:8-bit microcontrollers with DTMF generator, 8 kbytes OTP and 128 bytes EEPROM |
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