Hardware manual

Microcomputer Technical Q&A
73
Q&A No.: QAH8S-203
Category: DMAC
Subject: Difference between DMAC and DTC
Question
What is the difference between the DMAC and the DTC?
Answer
The DMAC has data transfer information registers within the module, and performs data transfer
on up to four channels. The DMAC achieves a high transfer speed of 0.1 µs (min.) per channel.
The DTC places transfer data information in on-chip RAM, and can perform transfer on up to 85
channels. The transfer speed is 0.65 µs per channel. The DTC can perform chain transfer in which
multiple data transfers are initiated by a single activation source.
Item DMAC DTC Notes
Minimum transfer time 0.1 µs 0.65 µs At 20 MHz operation
Transfer information Dedicated registers On-chip RAM
Activation sources 13 28 H8S/2655
Transfer channels 4 85
Chain transfer No Yes
Applicable Products
Applicability Series Applicability Series Applicability Series
Entire H8S Series Yes H8S/2655 Yes H8S/2350
H8S/2355 Yes H8S/2357 H8S/2345
H8S/2245 H8S/2148 H8S/2144
H8S/2138 H8S/2134 H8S/2128
H8S/2124 — — — —