11. DMAC
puorG92/C61M
page 97
854fo7002,03.raM21.1.veR
2110-1010B90JER
Figure 11.5 Transfer Cycles for Source Read
CPU clock
Address
bus
RD signal
WR signal
Data
bus
CPU use
CPU use CPU use
CPU useSource
Source
Destination
Destination
Dummy
cycle
Dummy
cycle
(1) When the transfer unit is 8 or 16 bits and the source of transfer is an even address
Address
bus
RD signal
WR signal
Data
bus
CPU use
CPU use CPU use
CPU use
Source
Source
Destination
Destination
Dummy
cycle
Dummy
cycle
(3) When the source read cycle under condition (1) has one wait state inserted
Address
bus
RD signal
WR signal
Data
bus
CPU use
CPU use
CPU use
CPU useSource
Source
Destination
Destination
Dummy
cycle
Dummy
cycle
Source + 1
Source + 1
(2) When the transfer unit is 16 bits and the source address of transfer is an odd address.
Address
bus
RD signal
WR signal
Data
bus
CPU use
CPU use
CPU use
CPU useSource
Source
Destination
Destination
Dummy
cycle
Dummy
cycle
Source + 1
Source + 1
(4) When the source read cycle under condition (2) has one wait state inserted
NOTE:
1. The same timing changes occur with the respective conditions at the destination as at the source.
CPU clock
CPU clock
CPU clock