tmp19a44fda TOSHIBA Semiconductor CORPORATION, tmp19a44fda Datasheet - Page 476

• Manufacturer Part Number: tmp19a44fda
• Description: 32bit Tx System Risc
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Analog/Digital Converter
17.3.3
Two types of A/D conversion are supported: normal AD conversion and top-priority AD conversion.
Normal AD conversion is software activated by setting ADnMOD0<ADS> to "1." Top-priority AD
conversion is software activated by setting ADnMOD2<HPADCE> to "1." 4 operation modes are made
available to normal AD conversion. In performing normal AD conversion, one of these operation modes
must be selected by setting ADnMOD0<2:1> to an appropriate setting. For top-priority AD conversion,
only one operation mode can be used: fixed channel single conversion mode. Normal AD conversion
can be activated using the HW activation source selected by ADnMOD4<ADHS>, and top-priority AD
conversion can be activated using the HW activation source selected by ADnMOD4<HADHS>. If this
bit is "0," normal and top-priority AD conversions are activated in response to the input of a falling edge
through the ADTRGn
bit timer 1, and top-priority AD conversion is activated in response to TB9TRG generated by the 16-bit
timer 9. Software activation is still valid even after H/W activation has been authorized.
Each unit has a pin (unit A: ADTRGA, unit B: ADTRGB, unit C: ADTRGC) that is used exclusively for
an external trigger.
Inputting an external trigger from ADTRGSNC pin allows unit A and unit B to start simultaneously.
When normal A/D conversion starts, the A/D conversion Busy flag (ADnMOD0<ADBF>) showing that
A/D conversion is under way is set to "1." When top-priority A/D conversion starts, the A/D conversion
Busy flag (ADnMOD2<ADBFHP>) showing that A/D conversion is under way is set to "1." If normal
A/D conversion is interrupted by top-priority A/D conversion, the value of the Busy flag for normal
A/D conversion before the start of top-priority A/D conversion is retained. The value of the conversion
completion flag EOCFN for normal A/D conversion before the start of top-priority A/D conversion can
also be retained.
(Note)
To reactivate normal A/D conversion, a software reset (ADnMOD4<ADRST1:0>) must be performed
before starting A/D conversion. The HW activation method must not be used to reactivate normal A/D
conversion.
If ADnMOD2<HPADCE> is set to "1" during normal A/D conversion, ongoing A/D conversion is
discontinued and top-priority A/D conversion starts; specifically, A/D conversion (fixed channel single
conversion) is executed for a channel designated by ADnMOD2<3:0>. After the result of this top-
priority A/D conversion is stored in the storage register ADnREGSP, normal A/D conversion is resumed.
If HW activation of top-priority A/D conversion is authorized during normal A/D conversion, ongoing
A/D conversion is discontinued when requirements for activation using a resource are met, and top-
priority A/D conversion (fixed channel single conversion) starts for a channel designated by
ADnMOD2<3:0>. After the result of this top-priority A/D conversion is stored in the storage register
ADnREGSP, normal A/D conversion is resumed.
pin. If this bit is "1," normal AD conversion is activated in response to TB1TRG generated by the 16-
(Note)
Starting A/D Conversion
When an external trigger is used for the HW start source of a top priority analog to
Normal A/D conversion must not be activated when top-priority A/D
conversion is under way. If activated when top-priority A/D conversion is
under way, the top-priority A/D conversion completion flag cannot be set, and
the flag for previous normal A/D conversion cannot be cleared.
digital translation, an external trigger cannot usually be set as analog to digital
translation HW start.
TMP19A44(rev1.3) 17-17
TMP19A44
2010-04-01