TMP86CH72FG Datasheet, PDF (164/198 Pages) Toshiba Semiconductor – 8 Bit Microcontroller

15. 8-Bit AD Converter (ADC)
15.3 Function
TMP86CH72FG
15.3 Function
15.3.1 AD Conveter Operation
When ADCCR1<ADRS> is set to "1", AD conversion of the voltage at the analog input pin specified by
ADCCR1<SAIN> is thereby started.
After completion of the AD conversion, the conversion result is stored in AD converted value registers
(ADCDR1) and at the same time ADCDR2<EOCF> is set to “1”, the AD conversion finished interrupt
(INTADC) is generated.
ADCCR1<ADRS> is automatically cleared after AD conversion has started. Do not set ADCCR1<ADRS>
newly again (restart) during AD conversion. Before setting ADRS newly again, check ADCDR<EOCF> to see
that the conversion is completed or wait until the interrupt signal (INTADC) is generated (e.g., interrupt han-
dling routine).
ADCCR1<ADRS>
AD conversion start
AD conversion start
ADCDR2<ADBF>
ADCDR1 status
Indeterminate
ADCDR2<EOCF>
INTADC interrupt
Reading ADCDR1
First conversion result
Conversion
result read
Second conversion result
EOCF cleared by reading
conversion result
Conversion
result read
Reading ADCDR2
Figure 15-2 AD Converter Operation
15.3.2 AD Converter Operation
1. Set up the AD converter control register 1 (ADCCR1) as follows:
• Choose the channel to AD convert using AD input channel select (SAIN).
• Specify analog input enable for analog input control (AINDS).
2. Set up the AD converter control register 2 (ADCCR2) as follows:
• Set the AD conversion time using AD conversion time (ACK). For details on how to set the con-
version time, refer to Table 15-1.
• Choose IREFON for DA converter control.
3. After setting up 1. and 2. above, set AD conversion start (ADRS) of AD converter control register 1
(ADCCR1) to “1”.
4. After an elapse of the specified AD conversion time, the AD converted value is stored in AD con-
verted value register 1 (ADCDR1) and the AD conversion finished flag (EOCF) of AD converted
value register 2 (ADCDR2) is set to “1”, upon which time AD conversion interrupt INTADC is gener-
ated.
5. EOCF is cleared to “0” by a read of the conversion result. However, if reconverted before a register
read, although EOCF is cleared the previous conversion result is retained until the next conversion is
completed.
Page 154