M306H2MC-XXXFP Datasheet, PDF (133/210 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

MITSUBISHI MICROCOMPUTERS
M306H2MC-XXXFP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
with DATA ACQUISITION CONTROLLER
2.12 A-D Converter
The A-D converter consists of one 8-bit successive approximation A-D converter circuit with a capacitive
coupling amplifier. Pins P100 to P107, P95, and P96 also function as the analog signal input pins. The
direction registers of these pins for A-D conversion must therefore be set to input. The Vref connect bit (bit
5 at address 03D716) can be used to isolate the resistance ladder of the A-D converter from the reference
voltage input pin (VREF) when the A-D converter is not used. Doing so stops any current flowing into the
resistance ladder from VREF, reducing the power dissipation. When using the A-D converter, start A-D
conversion only after setting bit 5 of 03D716 to connect VREF.
The result of A-D conversion is stored in the A-D registers of the selected pins.
Table 2.12.1 shows the performance of the A-D converter. Figure 2.12.1 shows the block diagram of the
A-D converter, and Figures 2.12.2 and 2.12.3 show the A-D converter-related registers.
Table 2.12.1 Performance of A-D converter
Item
Performance
Method of A-D conversion Successive approximation (capacitive coupling amplifier)
Analog input voltage (Note 1) 0V to AVCC (VCC)
Operating clock φ AD (Note 2) fAD/divide-by-2 of fAD/divide-by-4 of fAD, fAD=f(XIN)
Resolution
Absolute precision
8-bit
q Without sample and hold function
±3LSB
q With sample and hold function
±2LSB
Operating modes
One-shot mode, repeat mode, single sweep mode, repeat sweep mode 0,
and repeat sweep mode 1
Analog input pins
8 pins (AN0 to AN7) + 2pins (ANEX0 and ANEX1)
A-D conversion start condition q Software trigger
A-D conversion starts when the A-D conversion start flag changes to “1”
q External trigger (can be retriggered)
A-D conversion starts when the A-D conversion start flag is “1” and the
__________
ADTRG/P97 input changes from “H” to “L”
Conversion speed per pin q Without sample and hold function
49 φ AD cycles
q With sample and hold function
28 φ AD cycles
Note 1: Does not depend on use of sample and hold function.
Note 2: Without sample and hold function, set the φAD frequency to 250kHZ min.
With the sample and hold function, set the φAD frequency to 1MHZ min.
Rev. 1.0
132