 |
전자부품 데이터시트 검색엔진 |
|
|
전자부품 데이터시트 검색엔진 |
|
HT56R22 데이터시트(PDF) 29 Page - Holtek Semiconductor Inc |
|
||||||||||||||||||||||||||||||
HT56R22 데이터시트(HTML) 29 Page - Holtek Semiconductor Inc |
|
|
29 / 127 page  HT56R22/HT56R23/HT56R24/HT56R25/HT56R26 Rev. 1.30 29 December 26, 2014 External RC Oscillator - ERC Using the ERC oscillator only requires that a resistor, with a value between 47k W and 1.5MW, is connected between OSC1 and VDD, and a capacitor is connected between OSC and ground, providing a low cost oscilla- tor configuration. It is only the external resistor that de- termines the oscillation frequency; the external capacitor has no influence over the frequency and is connected for stability purposes only. Device trimming during the manufacturing process and the inclusion of internal frequency compensation circuits are used to en- sure that the influence of the power supply voltage, tem- perature and process variations on the oscillation frequency are minimised. As a resistance/frequency ref- erence point, it can be noted that with an external 150k W resistor connected and with a 5V voltage power supply and temperature of 25 degrees, the oscillator will have a frequency of 4MHz within a tolerance of 2%. Here only the OSC1 pin is used, which is shared with I/O pin PC0, leaving pin PC1 free for use as a normal I/O pin. For oscillator stability and to minimise the effects of noise and crosstalk, it is important to locate the capaci- tor and resistoras close to the MCU as possible. Internal RC Oscillator - HIRC The internal RC oscillator is a fully integrated system os- cillator 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 fre- quency compensation circuits are used to ensure that the influence of the power supply voltage, temperature and process variations on the oscillation frequency are minimised. As a result, at a power supply of either 3V or 5V and at a temperature of 25 degrees, the fixed oscilla- tion frequency of 4MHz, 8MHz or 12MHz will have a tol- erance within 2%. Note that if this internal system clock option is selected, as it requires no external pins for its operation, I/O pins PC1 and PC0 are free for use as nor- mal I/O pins. 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 low speed oscillator, known as the LXT oscillator to be used. The LXT oscillator is implemented using a 32768Hz crystal connected to pins. However, for some crystals, to ensure oscillation and accurate frequency generation, it is necessary to add two small value exter- nal capacitors, C1 and C2. The exact values of C1 and C2 should be selected in consultation with the crystal or resonator manufacturer ¢s specification. The external parallel feedback resistor, RP2, is required. For oscillator stability and to minimise the effects of noise and crosstalk, it is important to ensure that the crystal and any associated resistors and capacitors along with inter connecting lines are all located as close to the MCU as possible. LXT Oscillator C1 and C2 Values Crystal Frequency C1 C2 32768Hz 8pF 10pF Note: 1. C1 and C2 values are for guidance only. 2. RP2=5M~10M W is recommended. 32768 Hz Crystal Recommended Capacitor Values For the devices, a configuration option determines if the XT1/XT2 pins are used for the LXT oscillator or as I/O pins. · If the I/O option is selected then the XT1/XT2 pins can be used as normal I/O pins. · If the ²LXT oscillator²is selected then the 32768Hz crystal should be connected to the XT1/ XT2 pins. P C 1 / O S C 1 4 7 0 p F V D D R O S C P C 0 / O S C 2 External RC Oscillator - ERC P C 0 / P C 1 u s e d a s n o r m a l I / O s N o t e : I n t e r n a l R C O s c i l l a t o r P C 1 / O S C 2 P C 0 / O S C 1 Internal RC Oscillator - HIRC T o i n t e r n a l c i r c u i t s I n t e r n a l O s c i l l a t o r C i r c u i t C 1 C 2 R P 2 N o t e : 1 . R p , C 1 a n d C 2 a r e r e q u i r e d . 2 . A l t h o u g h n o t s h o w n p i n s h a v e a p a r a s i t i c c a p a c i t a n c e o f a r o u n d 7 p F . I n t e r n a l R C O s c i l l a t o r 3 2 7 6 8 H z External 32768Hz Crystal Oscillator - LXT |
유사한 부품 번호 - HT56R22_14 |
|
유사한 설명 - HT56R22_14 |
|
|
링크 URL |
| 개인정보취급방침 |
| ALLDATASHEET.CO.KR |
| ALLDATASHEET 가 귀하에 도움이 되셨나요? [ DONATE ] |
Alldatasheet는? | 광고문의 | 운영자에게 연락하기 | 개인정보취급방침 | 링크교환 | 제조사별 검색 All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
Korean ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
