Go to the source code of this file.
Defines | |
| #define | CLOCK_CONFIG SIM_CLOCK |
#defines for CLOCK_CONFIG | |
| #define | SIM_CLOCK 0, -1, 1000000L, POSCMD_NONE, -1, 1, configClockSim, 498 |
| #define | FRCPLL_FCY16MHz 1, FNOSC_FRCPLL, 16000000L, POSCMD_NONE, -1, PIC24F_DEFINED, configClockFRCPLL_FCY16MHz, 498 |
| #define | FRC_FCY4MHz 2, FNOSC_FRC, 4000000L, POSCMD_NONE, -1, PIC24F_DEFINED, configClockFRC_FCY4MHz, 498 |
| #define | PRI_NO_PLL_7372KHzCrystal 3, FNOSC_PRI, 3686400L, POSCMD_XT, 7372800L, (PIC24F_DEFINED || PIC24H_DEFINED), configClockPRI_NO_PLL_7372KHzCrystal, 498 |
| #define | FRC_FCY3685KHz 4, FNOSC_FRC, 3685000L, POSCMD_NONE, -1, PIC24H_DEFINED, configClockFRC_FCY3685KHz, 498 |
| #define | FRCPLL_FCY40MHz 5, FNOSC_FRCPLL, 40000000L, POSCMD_NONE, -1, PIC24H_DEFINED, configClockFRCPLL_FCY40MHz, 498 |
| #define | PRIPLL_7372KHzCrystal_40MHzFCY 6, FNOSC_PRIPLL, 40000000L, POSCMD_XT, 7372800L, PIC24H_DEFINED, configClockPRIPLL_7372KHzCrystal_40MHzFCY, 498 |
| #define | PRIPLL_8MHzCrystal_40MHzFCY 7, FNOSC_PRIPLL, 40000000L, POSCMD_XT, 8000000L, PIC24H_DEFINED, configClockPRIPLL_8MHzCrystal_40MHzFCY, 498 |
| #define | PRIPLL_8MHzCrystal_16MHzFCY 8, FNOSC_PRIPLL, 16000000L, POSCMD_XT, 8000000L, PIC24F_DEFINED, configClockPRIPLL_8MHzCrystal_16MHzFCY, 498 |
Some of the #defines produced by CLOCK_CONFIG choice | |
| #define | CLOCK_CONFIG_INDEX GET_CLOCK_CONFIG_INDEX(CLOCK_CONFIG) |
| #define | FNOSC_SEL GET_FNOSC_SEL(CLOCK_CONFIG) |
| #define | FCY GET_FCY(CLOCK_CONFIG) |
| #define | POSCMD_SEL GET_POSCMD_SEL(CLOCK_CONFIG) |
| #define | POSC_FREQ GET_POSC_FREQ(CLOCK_CONFIG) |
| #define | CONFIG_DEFAULT_CLOCK() GET_CONFIG_DEFAULT_CLOCK(CLOCK_CONFIG)() |
Helper macros for clock configuration | |
| #define | IS_CLOCK_CONFIG(clockConfig) _GET_CLOCK_CONFIG_INDEX(clockConfig) == CLOCK_CONFIG_INDEX |
| #define | GET_OSC_SEL_BITS(bits) _GET_OSC_SEL_BITS(bits) |
| #define | OSC_SEL_BITS GET_OSC_SEL_BITS(FNOSC_SEL) |
Functions | |
| static void | configClock () |
| void | switchClock (uint8 u8_source) |
configClock() functions for various clock setups | |
| void | configClockSim (void) |
To choose a clock configuration, simply select a value for CLOCK_CONFIG from the table there. The default selection used by most of the PIC24H examples is FRCPLL_FCY40MHz (the internal FRC+ PLL configured for FCY = 40 MHz). Some of the examples in Chapter 12 expect an external 8 MHz crystal, and use the PRIPLL_8MHzCrystal_40MHzFCY option (external 8 MHz crystal + PLL confgured for FCY = 40 MHz). If CLOCK_CONFIG is not defined, the default choice for PIC24H processors is FRCPLL_FCY40MHz, while for PIC24F processors the default is FRCPLL_FCY16MHz (internal FRC+ PLL configured for FCY = 16 MHz).
This file provides several useful defines as a result of the clock selection above:
To define a new clock configuation:
Definition in file pic24_clockfreq.h.
| #define CLOCK_CONFIG SIM_CLOCK |
Clock configuration for the PIC24 - set CLOCK_CONFIG to one of the following. Naming convention is OSCTYPE_[PRIFREQ]_FCYFREQ where OSCTYPE gives the oscillator type (see FNOSC_SEL for details), the optional PRIFREQ specifies primary oscillator frequency, and FCYFREQ determiens the processor clock (FCY) frequency. The "#defines for CLOCK_CONFIG" section gives the definition of the values below.
Name uP --------------- --- SIM_CLOCK (simulator) any FRCPLL_FCY16MHz 24F FRC_FCY4MHz 24F PRIPLL_8MHzCrystal_16MHzFCY 24F PRI_NO_PLL_7372KHzCrystal 24F, 24H FRC_FCY3685KHz 24H FRCPLL_FCY40MHz 24H PRIPLL_7372KHzCrystal_40MHzFCY 24H PRIPLL_8MHzCrystal_40MHzFCY 24H
Definition at line 97 of file pic24_clockfreq.h.
| #define CLOCK_CONFIG_INDEX GET_CLOCK_CONFIG_INDEX(CLOCK_CONFIG) |
A unique number is assigned to each clock configuration, in order to allow comparsions between configurations. CLOCK_CONFIG_INDEX gives the number assigned to the selected clock configuration. The macro IS_CLOCK_CONFIG uses this number for its comparsisons.
| #define CONFIG_DEFAULT_CLOCK | ( | ) | GET_CONFIG_DEFAULT_CLOCK(CLOCK_CONFIG)() |
Calls one of the configClock() functions defined in pic24_clockfreq.c based on the CLOCK_CONFIG chosen.
| #define FCY GET_FCY(CLOCK_CONFIG) |
FCY specifies the resulting processor clock frequency after all PLL/divide operations take the inital clock and produce a processor clock. The units of this value are Hz, so the value 40000000L is 40 MHz.
NOTE: This should be defined as a long (with a trailing L after the number) to allocate enough space to correctly store the processor clock frequency.
| #define FNOSC_SEL GET_FNOSC_SEL(CLOCK_CONFIG) |
Oscillator source selection for the PIC24. FNOSC_SEL is set to one of the following based on CLOCK_CONFIG :
Name Description PIC24F PIC24H
------------- -------------------------------------------- ------ ------
FNOSC_FRC Fast RC oscillator X X
FNOSC_FRCPLL Fast RC oscillator w/ divide and PLL X X
FNOSC_PRI Primary oscillator (XT, HS, EC) X X
FNOSC_PRIPLL Primary oscillator (XT, HS, EC) w/ PLL X X
FNOSC_SOSC Secondary oscillator X X
FNOSC_LPRC Low power RC oscillator X X
FNOSC_FRCDIV Fast RC oscillator with divide X
FNOSC_FRCDIV16 Fast RC oscillator w/ divide by 16 X
FNOSC_LPRCDIVN Low power Fast RC oscillator w/divide by N X
| #define GET_OSC_SEL_BITS | ( | bits | ) | _GET_OSC_SEL_BITS(bits) |
A macro to determine the NOSC/COSC bits for the OSCCON register given bits taken from the PIC24's configuration FNOSC word.
Definition at line 332 of file pic24_clockfreq.h.
| #define IS_CLOCK_CONFIG | ( | clockConfig | ) | _GET_CLOCK_CONFIG_INDEX(clockConfig) == CLOCK_CONFIG_INDEX |
A helper macro to check if the given clock configuration was selected. Example usage is given in pic24_clockfreq.c. A shorter example:
#if IS_CLOCK_CONFIG(FRCPLL_FCY40MHz) ... code only included if CLOCK_CONFIG is FRCPLL_FCY40MHz ... #endif
| clockConfig | Clock configuration to compare the current clock configuation against. |
Definition at line 326 of file pic24_clockfreq.h.
| #define OSC_SEL_BITS GET_OSC_SEL_BITS(FNOSC_SEL) |
A macro giving the NOSC/COSC bits for the OSCCON register which correspond to FNOSC_SEL, the configuration word which contains the FNOSC bits.
Definition at line 345 of file pic24_clockfreq.h.
| #define POSC_FREQ GET_POSC_FREQ(CLOCK_CONFIG) |
This values gives the primary osciallator frequency (if used). The units of this value are Hz, so the value 40000000L is 40 MHz.
NOTE: This should be defined as a long (with a trailing L after the number) to allocate enough space to correctly store the processor clock frequency.
| #define POSCMD_SEL GET_POSCMD_SEL(CLOCK_CONFIG) |
Specifies the primary oscillator type. Valid values:
POSCMD_EC External clock
POSCMD_XT XT oscillator (for crystals from 3.5 MHz to 10 MHz)
POSCMD_HS HS oscillator (for crystals from 10 MHz to 32 MHz)
POSCMD_NONE Primary oscillator disabled
| #define SIM_CLOCK 0, -1, 1000000L, POSCMD_NONE, -1, 1, configClockSim, 498 |
Create a table of vales for CLOCK_CONFIG. When adding a new entry, you must also write C code to configure the clock in pic24_clockfreq.c. See that file for examples and the detailed description section at the top of this page for more information. Note that FCY and POSC_FREQ should be defined as a long (with a trailing L) to retain enough accuracy to store these values.
Table entry notes: (see actual code, not the documentation, for the table)
Definition at line 135 of file pic24_clockfreq.h.
| static void configClock | ( | ) | [inline, static] |
Configure the default clock by calling the CONFIG_DEFAULT_CLOCK() macro.
Definition at line 407 of file pic24_clockfreq.h.
| void configClockSim | ( | void | ) |
Nothing to do! Simulator clock not set by OSCCON, but instead in the Debugger | Settings, Osc/Trace dialog box. It should be 2 MHz there, since that's Fosc = 2*Fcy. At 1 MHz, simulation speed seems fast enough to execute a reasonable amount of code. Also, at a 64K line trace buffer, we can see 64 ms of execution, which is plenty to see 20 ms servo pulses.
| void switchClock | ( | uint8 | u8_source | ) |
Switch the clock to the source specified. The source given will be assigned to NOSC in the OSCCON register, the a switch clock performed.
Note: DO NOT use FNOSC_SEL as the source; instead, use OSC_SEL_BITS. FNOSC_SEL is for configuration bits while switchClock expects a NOSC value to write to the OSCCON register.
| u8_source | The clock source to switch to. |
Definition at line 170 of file pic24_clockfreq.c.
1.5.8