HT48R065G View Datasheet(PDF) - Holtek Semiconductor
Part Name
Description
MFG CO.
'HT48R065G' PDF : 126 Pages View PDF
HT48R064G/065G/066G/0662G
Enhanced I/O Type 8-Bit OTP MCU with OPA
Internal RC Oscillator - HIRC
The internal RC oscillator is a fully integrated system oscillator requiring no external components. The
internal RC oscillator has three fixed frequencies of either 4MHz, 8MHz or 12MHz. Device trimming
during the manufacturing process and the inclusion of internal frequency compensation circuits are
used to ensure that the influence of the power supply voltage, temperature and process variations on
the oscillation frequency are minimised. Refer to the A.C. Characteristics for more frequency accuracy
details. Note that if this internal system clock option is selected, as it requires no external pins for its
operation, I/O pins PA5 and PA6 are free for use as normal I/O pins or the LXT oscillator pins
depending upon the selected device.
P A 5 /O S C 2
P A 6 /O S C 1
In te rn a l R C
O s c illa to r
N o te : P A 5 /P A 6 u s e d a s n o rm a l I/O s
Internal RC Oscillator - HIRC
External 32768Hz Crystal Oscillator - LXT
When the microcontroller enters the Idle/Sleep Mode, the system clock is switched off to stop
microcontroller activity and to conserve power. However, in many microcontroller applications it may
be necessary to keep the internal timers operational even when the microcontroller is in the
Power-down Mode. To do this, another clock, independent of the system clock, must be provided. To
do this a configuration option exists to allow a high speed oscillator to be used in conjunction with a
low speed oscillator, known as the LXT oscillator. The LXT oscillator is implemented using a
32768Hz crystal connected to pins OSC1/OSC2 for the HT48R064G/HT48R065G or connected to
pins OSC3/OSC4 for the HT48R0662G. However, for some crystals, to ensure oscillation and
accurate frequency generation, it is necessary to add two small value external capacitors, C1 and C2.
The exact values of C1 and C2 should be selected in consultation with the crystal or resonator
manufacturers specification. The external parallel feedback resistor, Rp, is required. For the
HT48R064G/HT48R065G devices the LXT oscillator must be used together with the HIRC oscillator.
For the HT48R0662G device the LXT oscillator must be used together with the HXT, ERC or HIRC
register.
C1
32768H z
Rp
C2
In te r n a l
O s c illa to r
C ir c u it
In te rn a l R C
O s c illa to r
T o in te r n a l
c ir c u its
N o te : 1 . R p , C 1 a n d C 2 a r e r e q u ir e d .
2 . A lth o u g h n o t s h o w n p in s h a v e a
p a r a s itic c a p a c ita n c e o f a r o u n d 7 p F .
External LXT Oscillator - LXT
Rev. 1.10
39
October 23, 2012
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