M306H7MG-XXXFP Datasheet, PDF (177/329 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

M306H7MG-XXXFP/MC-XXXFP/FGFP
12. A/D CONVERTER
12.6 Sample and Hold
If the ADCON2 register’s SMP bit is set to “1” (with sample-and-hold), the conversion speed per pin is increased
to 28 φAD cycles for 8-bit resolution. Sample-and-hold is effective in all operation modes.
Select whether or not to use the sample-and-hold function before starting A/D conversion.
12.7 Extended Analog Input Pins
In one-shot and repeat modes, the ANEX0 and ANEX1 pins can be used as analog input pins. Use the ADCON1
register’s OPA1 to OPA0 bits to select whether or not use ANEX0 and ANEX1.
The A/D conversion results of ANEX0 and ANEX1 inputs are stored in the AD0 and AD1 registers, respectively.
12.8 External Operation Amp Connection Mode
Multiple analog inputs can be amplified using a single external op-amp via the ANXE0 and ANEX1 pins.
Set the ADCON1 register’s OPA1 OPA0 bits to ‘112’ (external op-amp connection mode). The inputs from ANi (i
= 0 to 7) are output from the ANEX0 pin. Amplify this output with an external op-amp before sending it back to the
ANEX1 pin. The A/D conversion result is stored in the corresponding ADi register. The A/D conversion speed
depends on the response characteristics of the external op-amp. Note that the ANXE0 and ANEX1 pins cannot be
directly connected to each other. Figure 12.9 is an example of how to connect the pins in external operation amp.
AN0
AN1
AN2
AN3
AN4
AN5
AN6
AN7
ANEX0
ANEX1
External op-
amp
Figure 12.9 External Op-amp Connection
Microcomputer
Resistor ladder
Successive conversion
register
Comparator
Rev.2.10 Oct 25, 2006 Page 177 of 326
REJ03B0152-0210