M30622MA-XXXFP RENESAS [Renesas Technology Corp], M30622MA-XXXFP Datasheet - Page 487

• Manufacturer Part Number: M30622MA-XXXFP
• Description: 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY
• Manufacturer: RENESAS [Renesas Technology Corp]

DMAC Applications
472
3.6 Memory to Memory DMA Transfer
Overview
Specifications
Operation
Figure 3.6.1. Operation timing of memory to memory DMA transfer
Address bus
RD signal
WR signal
Timer A0
transfer request
Note 1:
Note 2:
Note 3:
The following are steps for changing both source address and destination address to transfer
data from memory to another. The DMA transfer utilizes the workings that assign a higher priority
to the DMA0 transfer if transfer requests simultaneously occur in two DMA channels. Figure
3.6.1 shows the operation timing, Figure 3.6.2 shows the block diagram, and Figures 3.6.3 and
3.6.4 show the set-up procedure.
Use the following peripheral functions:
• Timer mode of timer A
• Two DMAC channels
• One-byte temporary RAM (address 0800
(1) Transfer the content of memory extending over 128 bytes from address A0000
(2) Use DMA0 for a transfer from the source to built-in memory, and DMA1 for a transfer from
(1) A timer A interrupt request occurs. Though both a DMA0 transfer request and a DMA1 trans-
(2) DMA0 receives a transfer request and transfers data from the source to the built-in memory.
(3) Next, DMA1 receives a transfer request and transfers data involved from built-in memory to
byte area starting from address C0000
request occurs.
built-in memory to the destination.
fer request occur simultaneously, the former is executed first.
At this time, the source address is incremented.
the destination. At this time, the destination address is incremented.
The DMA0 operation and DMA1 operation are not necessarily executed in succession
due to the a cycle steal operation.
The instruction cycle varies from instruction to instruction.
Since the parts of the RD and WR signals shown in short-dash lines vary in step with
writing to the internal RAM, waveforms are not output to the RD and WR pins.
“1”
“0”
“1”
“0”
“1”
“0”
Instruction cycle
(1) Transfer request generation
(2) Start DMA0 transferring
Source address
A0000
DMA0 operation
16
16
16
. Transfer the content every time a timer A0 interrupt
)
Destination address
0800
16
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(3) Start DMA1 transferring
Source address
0800
DMA1 operation
16
Destination address
C0000
Mitsubishi microcomputers
M16C / 62 Group
16
16
to a 128-