MC9S08GT16A Datasheet, PDF (235/300 Pages) Freescale Semiconductor, Inc – Microcontrollers

Analog-to-Digital Converter (S08ATDV3)
14.5 Resets
The ATD module is reset on system reset. If the system reset signal is activated, the ATD registers are
initialized back to their reset state and the ATD module is powered down. This occurs as a function of the
register file initialization; the reset definition of the ATDPU bit (power down bit) is zero or disabled.
The MCU places the module back into an initialized state. If the module is performing a conversion, the
current conversion is terminated, the conversion complete flag is cleared, and the SAR register bits are
cleared. Any pending interrupts are also cancelled. Note that the control, test, and status registers are
initialized on reset; the initialized register state is defined in the register description section of this
specification.
Enabling the module (using the ATDPU bit) does not cause the module to reset since the register file is not
initialized. Finally, writing to control register ATDC does not cause the module to reset; the current
conversion will be terminated.
14.6 Interrupts
The ATD module originates interrupt requests and the MCU handles or services these requests. Details on
how the ATD interrupt requests are handled can be found in the resets and interrupts chapter of this data
sheet.
The ATD interrupt function is enabled by setting the ATDIE bit in the ATDSC register. When the ATDIE
bit is set, an interrupt is generated at the end of an ATD conversion and the ATD result registers (ATDRH
and ATDRL) contain the result data generated by the conversion. If the interrupt function is disabled
(ATDIE = 0), then the CCF flag must be polled to determine when a conversion is complete.
The interrupt will remain pending as long as the CCF flag is set. The CCF bit is cleared whenever the ATD
status and control (ATDSC) register is written. The CCF bit is also cleared whenever the ATD result
registers (ATDRH or ATDRL) are read.
Table 14-8. Interrupt Summary
Interrupt
CCF
Local
Enable
ATDIE
Description
Conversion complete
MC9S08GT16A/GT8A Data Sheet, Rev. 1
Freescale Semiconductor
235