M16C/62P Group (M16C/62P, M16C/62PT)
14. DMAC
Rev.2.41
Jan 10, 2006
Page 134 of 390
REJ09B0185-0241
14.2
DMA Transfer Cycles
Any combination of even or odd transfer read and write addresses is possible. Table 14.2 lists the DMA Transfer
Cycles. Table 14.3 lists the Coefficient j, k.
The number of DMAC transfer cycles can be calculated as follows:
No. of transfer cycles per transfer unit = No. of read cycles × j + No. of write cycles × k
— : This condition does not exist.
NOTES:
1. Depends on the set value of CSE register.
2. Depends on the set value of PM20 bit in the PM2 register.
Table 14.2
DMA Transfer Cycles
Transfer Unit
Bus Width
Access
Address
Single-Chip Mode
Memory Expansion Mode
Microprocessor Mode
No. of Read
Cycles
No. of Write
Cycles
No. of Read
Cycles
No. of Write
Cycles
8-bit Transfers
(DMBIT= 1)
16-bit
(BYTE= L)
Even
1
1
1
1
Odd
1
1
1
1
8-bit
(BYTE = H)
Even
—
—
1
1
Odd
—
—
1
1
16-bit Transfers
(DMBIT= 0)
16-bit
(BYTE = L)
Even
1
1
1
1
Odd
2
2
2
2
8-bit
(BYTE = H)
Even
—
—
2
2
Odd
—
—
2
2
Table 14.3
Coefficient j, k
Internal Area
External Area
Internal ROM,
RAM
SFR
Separate Bus
Multiplex Bus
No Wait
With
Wait
1-Wait
(2)
2-Wait
(2)
No
Wait
With Wait
(1)
With Wait
(1)
1-Wait
2-Wait
3-Wait
1-Wait
2-Wait
3-Wait
j
1
2
2
3
1
2
3
4
3
3
4
k
1
2
2
3
2
2
3
4
3
3
4
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