HD64570 HITACHI [Hitachi Semiconductor], HD64570 Datasheet - Page 42

• Manufacturer Part Number: HD64570
• Description: Serial Communications Adaptor
• Manufacturer: HITACHI [Hitachi Semiconductor]

1.7.9
The DMAC module in the SCA has four independent channels (figure 1.14). The DMAC is used
exclusively for single-address transfer between memory and the MSCI. Data can be transferred a
word at a time or a byte at a time. A group of data transferred consecutively is referred to as a
block. The DMAC can transfer single blocks individually, or can transfer a chained sequence of
blocks (chained-block transfer). See figure 1.15 to 1.20.
Features:
Rev. 0, 07/98, page 26 of 453
Data
bus
Four independent DMA channels
Programmable channel priority
Used exclusively for transfer between memory and MSCI
Single-block transfer or chained-block transfer (supported by buffer management function)
Two interrupt sources
Maximum transfer rate: 11.1 Mbytes/s (operating on 16.7 MHz clock)
Address space: 16 Mbytes
Figure 1.14 Interconnections between DMA Channels and MSCI Channels (concept)
DMAC
Channel 0
Channel 1
Channel 2
Channel 3
DMAC
transmitter
transmitter
Channel 0
Channel 0
Channel 1
Channel 1
receiver
receiver
MSCI
Receive data
Transmit data
Receive data
Transmit data