15.4.3 Hardware trigger
The ADC module has a selectable asynchronous hardware conversion trigger, ADHWT,
that is enabled when the ADC_SC2[ADTRG] bit is set. This source is not available on all
MCUs. See the module introduction for information on the ADHWT source specific to
this MCU.
When ADHWT source is available and hardware trigger is enabled
( ADC_SC2[ADTRG] = 1), a conversion is initiated on the rising edge of ADHWT. If a
conversion is in progress when a rising edge occurs, the rising edge is ignored. In
continuous convert configuration, only the initial rising edge to launch continuous
conversions is observed. The hardware trigger function operates in conjunction with any
of the conversion modes and configurations.
15.4.4 Conversion control
Conversions can be performed in 12-bit mode, 10-bit mode, or 8-bit mode as determined
by the ADC_SC3[MODE] bits. Conversions can be initiated by a software or hardware
trigger. In addition, the ADC module can be configured for low power operation, long
sample time, continuous conversion, and an automatic compare of the conversion result
to a software determined compare value.
15.4.4.1 Initiating conversions
A conversion initiates under the following conditions:
• A write to ADC_SC1 or a set of write to ADC_SC1 in FIFO mode (with ADCH bits
not all 1s) if software triggered operation is selected.
• A hardware trigger (ADHWT) event if hardware triggered operation is selected.
• The transfer of the result to the data registers when continuous conversion is enabled.
If continuous conversions are enabled, a new conversion is automatically initiated after
the completion of the current conversion. In software triggered operation, continuous
conversions begin after ADC_SC1 is written and continue until aborted. In hardware
triggered operation, continuous conversions begin after a hardware trigger event and
continue until aborted.
Chapter 15 Analog-to-digital converter (ADC)
MC9S08PA4 Reference Manual, Rev. 5, 08/2017
NXP Semiconductors
309
Содержание MC9S08PA4
Страница 1: ...MC9S08PA4 Reference Manual Supports MC9S08PA4 Document Number MC9S08PA4RM Rev 5 08 2017 ...
Страница 2: ...MC9S08PA4 Reference Manual Rev 5 08 2017 2 NXP Semiconductors ...
Страница 22: ...MC9S08PA4 Reference Manual Rev 5 08 2017 22 NXP Semiconductors ...
Страница 28: ...System clock distribution MC9S08PA4 Reference Manual Rev 5 08 2017 28 NXP Semiconductors ...
Страница 150: ...Port data registers MC9S08PA4 Reference Manual Rev 5 08 2017 150 NXP Semiconductors ...
Страница 196: ...Human machine interfaces HMI MC9S08PA4 Reference Manual Rev 5 08 2017 196 NXP Semiconductors ...
Страница 224: ...Instruction Set Summary MC9S08PA4 Reference Manual Rev 5 08 2017 224 NXP Semiconductors ...
Страница 232: ...Functional Description MC9S08PA4 Reference Manual Rev 5 08 2017 232 NXP Semiconductors ...
Страница 258: ...FTM Interrupts MC9S08PA4 Reference Manual Rev 5 08 2017 258 NXP Semiconductors ...
Страница 268: ...Initialization application information MC9S08PA4 Reference Manual Rev 5 08 2017 268 NXP Semiconductors ...
Страница 294: ...Functional description MC9S08PA4 Reference Manual Rev 5 08 2017 294 NXP Semiconductors ...
Страница 370: ...Memory map and register description MC9S08PA4 Reference Manual Rev 5 08 2017 370 NXP Semiconductors ...
Страница 398: ...Resets MC9S08PA4 Reference Manual Rev 5 08 2017 398 NXP Semiconductors ...
Страница 400: ...MC9S08PA4 Reference Manual Rev 5 08 2017 400 NXP Semiconductors ...