TMP91C824
91C824-188
2008-02-20
(3)
Starting AD conversion
To start AD conversion, write 1 to ADMOD0<ADS> in AD mode control register 0
or ADMOD1<ADTRGE> in AD mode control register 1 and input falling edge on
ADTRG
pin. When AD conversion starts, the AD conversion busy flag
ADMOD0<ADBF> will be set to 1, indicating that AD conversion is in progress.
Writing 1 to ADMOD0<ADS> during AD conversion restarts conversion. At that
time, to determine whether the AD conversion results have been preserved, check the
value of the conversion data storage flag ADREGxL<ADRxRF>.
During AD conversion, a falling edge input on the
ADTRG
pin will be ignored.
(4)
AD conversion modes and the AD conversion end interrupt
The 4 AD conversion modes are:
•
Channel fixed single conversion mode
•
Channel scan single conversion mode
•
Channel fixed repeat conversion mode
•
Channel scan repeat conversion mode
The ADMOD0<REPEAT> and ADMOD0<SCAN> settings in AD mode control
register 0 determine the AD mode setting.
Completion of AD conversion triggers an INTAD AD conversion end interrupt
request. Also, ADMOD0<EOCF> will be set to 1 to indicate that AD conversion has
been completed.
a.
Channel fixed single conversion mode
Setting ADMOD0<REPEAT> and ADMOD0<SCAN> to 00 selects channel
fixed single conversion mode.
In this mode, data on one specified channel is converted once only. When the
conversion has been completed, the ADMOD0<EOCF> flag is set to 1,
ADMOD0<ADBF> is cleared to 0, and an INTAD interrupt request is generated.
b.
Channel scan single conversion mode
Setting ADMOD0<REPEAT> and ADMOD0<SCAN> to 01 selects channel
scan single conversion mode.
In this mode, data on the specified scan channels is converted once only. When
scan conversion has been completed, ADMOD0<EOCF> is set to 1,
ADMOD0<ADBF> is cleared to 0, and an INTAD interrupt request is generated.