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3.11 Analog/Digital Converter
The TMP91C824 incorporates a 10-bit successive approximation-type analog/digital
converter (AD converter) with 8-channel analog input.
Figure 3.11.1 is a block diagram of the AD converter. The 8-channel analog input pins (AN0
to AN7) are shared with the input only port 8 and can thus be used as an input port.
Note: When IDLE2, IDLE1 or STOP mode is selected, so as to reduce the power, with some
timings the system may enter a standby mode even though the internal comparator is still
enabled. Therefore be sure to check that AD converter operations are halted before a
HALT instruction is executed.
AD mode control register 1 ADMOD1
ADMOD1
<ADCH2:0><VREFON>
Analog input
AN7 (P87)
AN6 (P86)
AN5 (P85)
AN4 (P84)
AN3/
(P83)
ADTRG
AN2 (P82)
AN1 (P81)
AN0 (P80)
VREFH
VREFL
Internal data bus
<ADTRGE>
<EOCF> <ADBF> <ITM0> <REPEAT> <SCAN> <ADS>
Channel
selector
Sample and
hold
Figure 3.11.1 Block Diagram of AD Converter
91C824-182
AD mode control register 0 ADMOD0
Repeat
Interrupt
Busy
End
AD converter control
circuit
+
−
Comparator
DA converter
TMP91C824
Scan
ADTRG
Start
INTAD
interrupt
AD conversion result
register
ADREG04L to ADREG37L
ADREG04H to ADREG37H
2008-02-20
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