Datasheet

Section 18 A/D Converter

R01UH0309EJ0500 Rev. 5.00 Page 1059 of 1408

Sep 24, 2012

H8S/2456, H8S/2456R, H8S/2454 Group

Section 18 A/D Converter

This LSI includes two units (units 0 and 1) of successive approximation type 10-bit A/D

converter. In the H8S/2456 group and H8S/2456R group, the A/D converter units 0 and 1 allow up

to eight analog input channels to be selected. In the H8S/2454 group, unit 0 allows up to eight

analog input channels to be selected while unit 1 allows up to two channels.

Figures 18.1 and 18.2 show block diagrams of the A/D converter units 0 and 1, respectively.

18.1 Features

• 10-bit resolution

• Input channels:

H8S/2456 group and H8S/2456R group: Eight channels (total of 16 channels for the two units)

H8S/2454 group: Eight channels for unit 0 and two channels for unit 1 (total of 10 channels for

the two units)

• Conversion cycle: 64 cycles or 40 cycles (A/D conversion clock)

• Two kinds of operating modes

⎯ Single mode: Single-channel A/D conversion

⎯ Scan mode: Continuous A/D conversion on 1 to 4 channels, or 1 to 8 channels*

• Separate A/D conversion clock specifiable for each unit (φ, φ/2, or φ/4)

• Eight data registers for A/D converter unit 0 and eight data registers for unit 1*

(total of 16

data registers for the two units)

Results of A/D conversion are held in a 16-bit data register for each channel.

• Sample and hold functionality

• Three types of conversion start

Conversion can be started by software, a conversion start trigger by the 16-bit timer pulse unit

(TPU) or 8-bit timer (TMR), or an external trigger signal.

• Interrupt source

A/D conversion end interrupt (ADI) request can be generated.

• Module stop state specifiable

Notes: 1. Continuous A/D conversion on 1 to 2 channels in the H8S/2454 group.

2. Two data registers for unit 1 (total of ten data registers for the two units) in the

H8S/2454 group.