M16C1N Datasheet, PDF (140/238 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/10 SERIES

M16C/1N Group
14. A/D Converter
14.3 Sample and Hold
Sample and hold is selected by setting bit 0 of the A/D control register 2 (address 00D416) to "1". When
sample and hold is selected, the rate of conversion of each pin increases. As a result, a 28 ØAD cycle is
achieved with 8-bit resolution and 33 ØAD with 10-bit resolution. Sample and hold can be selected in all
modes. However, in all modes, be sure to specify before starting A/D conversion whether sample and
hold is to be used.
14.4 Extended Analog Input Pins
In one-shot mode and repeat mode, the input via the extended analog input pins ANEX0 and ANEX1 can
also be converted from analog to digital.
When bit 6 of the A/D control register 1 (address 00D716) is "1" and bit 7 is "0", input via ANEX0 is
converted from analog to digital.
When bit 6 of the A/D control register 1 (address 00D716) is "0" and bit 7 is "1", input via ANEX1 is
converted from analog to digital.
14.5 External Operation Amp Connection Mode
In this mode, multiple external analog inputs via the extended analog input pins, ANEX0 and ANEX1, can
be amplified together by just one operation amp and used as the input for A/D conversion.
When bit 6 of the A/D control register 1 (address 00D716) is "1" and bit 7 is "1", input via AN0 to AN11 is
output from ANEX0. The input from ANEX1 is converted from analog to digital and the result stored in the
A/D register. The speed of A/D conversion depends on the response of the external operation amp. Do
not connect the ANEX0 and ANEX1 pins directly.
Figure 14.6 is an example of how to connect the pins in external operation amp mode.
Resistance ladder
Analog
input
AN0
AN1
AN2
AN3
AN4
AN5
AN6
AN7
AN8
AN9
AN10
AN11
ANEX0
Successive conversion register
ADGSEL0=0
ADGSEL0=1
ANEX1
External op-amp
Comparator
Figure 14.6 Example of external op-amp connection mode
Rev.1.00 Oct 20, 2004 page 128 of 222
REJ09B0007-0100Z