 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
RFPIC12C509AG Datasheet(PDF) 48 Page - Microchip Technology |
|
||||||||||||||||||||||||||||||
RFPIC12C509AG Datasheet(HTML) 48 Page - Microchip Technology |
|
|
48 / 104 page  rfPIC12C509AG/509AF DS70031A-page 46 Preliminary © 2001 Microchip Technology Inc. 8.2.4 INTERNAL 4 MHz RC OSCILLATOR The internal RC oscillator provides a fixed 4 MHz (nom- inal) system clock at VDD = 5V and 25°C, see “Electri- cal Specifications” section for information on variation over voltage and temperature. In addition, a calibration instruction is programmed into the top of memory which contains the calibration value for the internal RC oscillator. This location is never code protected regardless of the code protect settings. This value is programmed as a MOVLW XX instruction where XX is the calibration value, and is placed at the RESET vector. This will load the W register with the cal- ibration value upon RESET and the PC will then roll over to the users program at address 0x000. The user then has the option of writing the value to the OSCCAL Register (05h) or ignoring it. OSCCAL, when written to with the calibration value, will “trim” the internal oscillator to remove process variation from the oscillator frequency. For the rfPIC12C509AG/509AF bits <7:2>, CAL5- CAL0 are used for calibration. Adjusting CAL5-0 from 000000 to 111111 yields a higher clock speed. Note that bits 1 and 0 of OSCCAL are unimplemented and should be written as 0 when modifying OSCCAL for compatibility with future devices. 8.3 RESET The device differentiates between various kinds of RESET: a) Power-on Reset (POR) b) MCLR Reset during normal operation c) MCLR Reset during SLEEP d) WDT Time-out Reset during normal operation e) WDT Time-out Reset during SLEEP f) Wake-up from SLEEP on pin change Some registers are not RESET in any way; they are unknown on POR and unchanged in any other RESET. Most other registers are RESET to “RESET state” on Power-on Reset (POR), MCLR, WDT or Wake-up-on- Pin Change Reset during normal operation. They are not affected by a WDT Reset during SLEEP or MCLR Reset during SLEEP, since these RESETS are viewed as resumption of normal operation. The exceptions to this are TO,PD, and GPWUF bits. They are set or cleared differently in different RESET situations. These bits are used in software to determine the nature of reset. See Table 8-3 for a full description of RESET states of all registers. Note: Please note that erasing the device will also erase the pre-programmed internal calibration value for the internal oscillator. The calibration value must be read prior to erasing the part. so it can be repro- grammed correctly later. |
Similar Part No. - RFPIC12C509AG |
|
Similar Description - RFPIC12C509AG |
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List 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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
