Mitsubishi microcomputers
M16C / 61 Group
DMAC
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(2) DMAC transfer cycles
Any combination of even or odd transfer read and write addresses is possible. Table 1.15.2 shows the
number of DMAC transfer cycles.
The number of DMAC transfer cycles can be calculated as follows:
No. of transfer cycles per transfer unit = No. of read cycles x j + No. of write cycles x k
Table 1.15.2. No. of DMAC transfer cycles
Single-chip mode
Memory expansion mode
Microprocessor mode
Transfer unit
Bus width
Access address
No. of read No. of write No. of read No. of write
cycles
cycles
cycles
cycles
16-bit
(BYTE= “L”)
8-bit
Even
Odd
1
1
1
1
1
1
1
1
1
2
2
2
1
1
1
1
1
2
2
2
8-bit transfers
(DMBIT= “1”)
Even
Odd
—
—
1
—
—
1
(BYTE = “H”)
16-bit
Even
Odd
16-bit transfers
(DMBIT= “0”)
(BYTE = “L”)
8-bit
2
2
Even
Odd
—
—
—
—
(BYTE = “H”)
Coefficient j, k
Internal memory
External memory
Internal ROM/RAM Internal ROM/RAM SFR area Separate bus Separate bus
Multiplex
No wait
1
With wait
2
No wait
1
With wait
2
bus
3
2
67
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