m5m51016btp Renesas Electronics Corporation., m5m51016btp Datasheet - Page 223

• Manufacturer Part Number: m5m51016btp
• Description: Renesas 16-bit Single-chip Microcomputer M16c Family / M16c/20 Series
• Manufacturer: Renesas Electronics Corporation.

M30245 Group
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
(4) Functions selection
(5) Input to A/D converter and the relation of direction register
(6) Pins related to A/D converter
(7) A/D converter related registers
(a) Sample & Hold function
(b) 8-bit A/D to 10-bit A/D switching function
(c) A/D conversion by external trigger
(d) Connecting or cutting Vref
To use the A/D converter, set the direction register of the relevant port to input.
(a) AN
(b) AVcc pin
(c) V
(d) AVss pin
(e) AD
Figure 2.9.1 shows the memory map of A/D converter-related registers, and Figures 2.9.2 and 2.9.3
show A/D converter-related registers.
Sample & Hold function samples input voltage when A/D conversion starts and carries out A/D con-
version on the voltage sampled. When A/D conversion starts, input voltage is sampled for 3 cycles of
the operation clock. When the Sample & Hold function is selected, set the operation clock for A/D
conversion to 1 MHz or higher.
Either 8-bit resolution or 10-bit resolution can be selected. When 8-bit resolution is selected, the 8
higher-order bits of the 10-bit A/D are subjected to A/D conversion. The equations for 10-bit resolu-
tion and 8-bit resolution are given below:
The user can select software or an external pin input to start A/D conversion.
Cutting Vref allows decrease of the current flowing into the A/D converter. To decrease the
microcomputer's power consumption, cut Vref. To carry out A/D conversion, start A/D conversion 1
µs or longer after connecting Vref.
10-bit resolution
___________
8-bit resolution
REF
0
TRG
pin through AN
pin
pin
page 214 of 354
(Vref X n / 2
(Vref X n / 2
7
pin
10
8
Input pins of the A/D converter
Power source pin of the analog section
Input pin of reference voltage
GND pin of the analog section
Trigger input pin of the A/D converter
) – (Vref X 0.5 / 2
) – (Vref X 0.5 / 2
10
10
)
)
(n = 1 to 1023), 0 (n = 0)
(n = 1 to 255), 0 (n = 0)
2. A/D Converter