Hola, empezamos la carrera con este micro, antes de empezar a programar, quiero dar unas pequeñas explicaciones de sus registros, al menos, los que vamos a utilizar para nuestros programas
empezamos con el registro CONFIG1
COPRS (Out of STOP Mode) — COP Reset Period Selection Bit
1 = COP reset short cycle = (8176) × BUSCLKX4
0 = COP reset long cycle = (262,128) × BUSCLKX4
COPRS (In STOP Mode) — Auto Wakeup Period Selection Bit
1 = Auto wakeup short cycle = (29) × INTRCOSC
0 = Auto wakeup long cycle = (214) × INTRCOSC
LVISTOP — LVI Enable in Stop Mode Bit
When the LVIPWRD bit is clear, setting the LVISTOP bit enables the LVI to operate during stop mode.
Reset clears LVISTOP.
1 = LVI enabled during stop mode
0 = LVI disabled during stop mode
LVIRSTD — LVI Reset Disable Bit
LVIRSTD disables the reset signal from the LVI module.
1 = LVI module resets disabled
0 = LVI module resets enabled
LVIPWRD — LVI Power Disable Bit
LVIPWRD disables the LVI module.
1 = LVI module power disabled
0 = LVI module power enabled
LVI5OR3 — LVI 5-V or 3-V Operating Mode Bit
LVI5OR3 selects the voltage operating mode of the LVI module. The voltage mode selected for the
LVI should match the operating VDD for the LVI’s voltage trip points for each of the modes.
1 = LVI operates in 5-V mode
0 = LVI operates in 3-V mode
NOTE
The LVI5OR3 bit is cleared by a power-on reset (POR) only. Other resets
will leave this bit unaffected.
SSREC — Short Stop Recovery Bit
SSREC enables the CPU to exit stop mode with a delay of 32 BUSCLKX4 cycles instead of a 4096
BUSCLKX4 cycle delay.
1 = Stop mode recovery after 32 BUSCLKX4 cycles
0 = Stop mode recovery after 4096 BUSCLKX4 cycles
nos sirve para declarar si queremos alimentar al perro guardian, para la opcion lvi, al perro lo deshabilitamos con 0x09 en el registro
CONFIG2
este otro registro nos sirve para decir si queremos oscilador interno o externo, reset y si queremos habilitar la interrupcion externa
IRQPUD — IRQ Pin Pullup Control Bit
1 = Internal pullup is disconnected
0 = Internal pullup is connected between IRQ pin and VDD
IRQEN — IRQ Pin Function Selection Bit
1 = Interrupt request function active in pin
0 = Interrupt request function inactive in pin
OSCOPT1 and OSCOPT0 — Selection Bits for Oscillator Option
(0, 0) Internal oscillator
(0, 1) External oscillator
(1, 0) External RC oscillator
(1, 1) External XTAL oscillator
RSTEN — RST Pin Function Selection
1 = Reset function active in pin
0 = Reset function inactive in pin
para las opciones no reset, no interrupcion externa irq ponemos en este registro 0x00
ahora nos vamos con el registro de oscilador OSCTRIM
TRIM7–TRIM0 — Internal Oscillator Trim Factor Bits
These read/write bits change the size of the internal capacitor used by the internal oscillator. By
measuring the period of the internal clock and adjusting this factor accordingly, the frequency of the
internal clock can be fine tuned. Increasing (decreasing) this factor by one increases (decreases) the
period by approximately 0.2% of the untrimmed period (the period for TRIM = $80). The trimmed
frequency is guaranteed not to vary by more than ±5% over the full specified range of temperature and
voltage. The reset value is $80, which sets the frequency to 12.8 MHz (3.2 MHz bus speed) ±25%.
bueno, nos dice que
All devices are programmed with a trim value in a reserved FLASH location, $FFC0. This value can be
copied from the FLASH to the OSCTRIM register ($0038) during reset initialization.
Reset loads OSCTRIM with a default value of $80.
normalmente debemos configurar este registro con 0x80 si queremos una frecuencia de 12.8MHz y muy importante
WARNING
Bulk FLASH erasure will set location $FFC0 to $FF and the factory
programmed value will be lost.
esto lo debemos de tomar en cuenta a la hora de programar nuestro micro, este registro se utiliza cuando tenemos configurado el CONFIG2 con oscilador interno,para el externo hay otro registro
bueno, estos son los principales registros para empezar a entender este micro, en lo particular me ha gustado bastante este micro, bastante facil de entender, excelente para empezar con esta familia, mañana pongo como debemos de configurar el codewarrior para empezar nuestro primer programa, saludos