参数资料
型号: M37643F8HP
元件分类: 微控制器/微处理器
英文描述: 8-BIT, FLASH, 12 MHz, MICROCONTROLLER, PQFP80
封装: 12 X 12 MM, 0.50 MM PITCH, PLASTIC, LQFP-80
文件页数: 83/123页
文件大小: 1292K
代理商: M37643F8HP
Rev.2.00
Aug 28, 2006
page 60 of 119
7643 Group
REJ03B0054-0200
CLOCK GENERATING CIRCUIT
The 7643 group has two built-in oscillation circuits. An oscillation
circuit can be formed by connecting a resonator between XIN and
XOUT (XCIN and XCOUT). Use the circuit constants in accordance
with the resonator manufacturer’s recommended values. No exter-
nal resistor is needed between XIN and XOUT since a feed-back
resistor exists on-chip. (An external feed-back resistor may be
needed depending on conditions.) However, an external feed-back
resistor is needed between XCIN and XCOUT.
When using an external clock, input the clocks to the XIN or XCIN
pin and leave the XOUT or XCOUT pin open.
Immediately after power on, only the XIN oscillation circuit starts
oscillating, and XCIN and XCOUT pins function as I/O ports.
Frequency Control
The internal system clock can be selected among fSYN, f(XIN),
f(XIN)/2, and f(XCIN). The internal clock
φ is half the frequency of
internal system clock.
(1) fSYN clock
This is made by the frequency synthesizer. f(XIN) or f(XCIN) can be
selected as its input clock. See also section “FREQUENCY SYN-
THESIZER”.
(2) f(XIN) clock
The frequency of internal system clock is the frequency of XIN pin.
(3) f(XIN)/2 clock
The frequency of internal system clock is half the frequency of XIN
pin.
(4) f(XCIN) clock
The frequency of internal system clock is the frequency of XCIN
pin.
sNote
If you switch the oscillation between XIN - XOUT and XCIN - XCOUT,
stabilize both XIN and XCIN oscillations. The sufficient time is re-
quired for the XCIN oscillation to stabilize, especially immediately
after power on and at returning from the stop mode.
Fig. 56 Ceramic resonator or quartz-crystal oscillator exter-
nal circuit
Fig. 57 External clock input circuit
XCIN
XCOUT
XIN
XOUT
CIN
COUT
CCIN
CCOUT
Rf
Rd
Notes : Insert a damping resistor if required. The
resistance will vary depending on the oscillator and
the oscillation drive capacity setting. Use the value
recommended by the maker of the oscillator. Also,
if the oscillator manufacturer's data sheet specifies
that a feedback resistor be added external to the
chip though a feedback resistor exists on-chip,
insert a feedback resistor between XIN and XOUT
following the instruction.
Rd (Note)
VCC
VSS
XCIN
XCOUT
XIN
XOUT
Open
External oscillation
circuit
External oscillation
circuit
VCC
VSS
相关PDF资料
PDF描述
M37700E2AFS 16-BIT, UVPROM, 16 MHz, MICROCONTROLLER, CQCC80
M37700E2AXXXFP 16-BIT, OTPROM, 16 MHz, MICROCONTROLLER, PQFP80
M37701E2-XXXSP 16-BIT, OTPROM, 8 MHz, MICROCONTROLLER, PDIP64
M37702E4EXXXFP 16-BIT, OTPROM, 16 MHz, MICROCONTROLLER, PQFP80
M37702M2BXXXFP 16-BIT, MROM, 25 MHz, MICROCONTROLLER, PQFP80
相关代理商/技术参数
参数描述
M37643F8M8-XXXFP 制造商:RENESAS 制造商全称:Renesas Technology Corp 功能描述:SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
M37643M8E8-XXXFP 制造商:RENESAS 制造商全称:Renesas Technology Corp 功能描述:SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
M37643M8M8-XXXFP 制造商:RENESAS 制造商全称:Renesas Technology Corp 功能描述:SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
M3764A-12 制造商:OK International 功能描述:
M3765 制造商:未知厂家 制造商全称:未知厂家 功能描述:HORN/SIREN WITH SOFT CHIRP 6 ALARM SOUNDS