Rev. 1.0, 09/01, page 304 of 904
ø
Bus release
DMA single
DMA single
Address bus
DMA control
Channel
[2]
Transfer source/
destination
Idle
Idle
Idle
[1]
[3]
[5]
[4]
[6]
[7]
Acceptance resumes
Acceptance resumes
Bus release
Bus release
Transfer source/
destination
Request
Request
Request clear
period
Request clear
period
Minimum of
2 cycles
Minimum of
2 cycles
Single
Single
[1]
Acceptance after transfer enabling; the
pin low level is sampled on the rising edge of ø,
and the request is held.
[2] [5] The request is cleared at the next bus break, and activation is started in the DMAC.
[3] [6] Start of DMA cycle;
pin high level sampling on the rising edge of ø starts.
[4] [7] When the
pin high level has been sampled, acceptance is resumed after the single
cycle is completed. (As in [1], the
pin low level is sampled on the rising edge of ø, and
the request is held.)
Note: In write data buffer mode, bus breaks from [2] to [7] may be hidden, and not visible.
Figure 7.30 Example of
'5(4
'5(4
'5(4
'5(4
Pin Falling Edge Activated Single Address Mode Transfer
'5(4
pin sampling is performed every cycle, with the rising edge of the next ø cycle after the
end of the DMABCR write cycle for setting the transfer enabled state as the starting point.
When the
'5(4
pin low level is sampled while acceptance by means of the
'5(4
pin is
possible, the request is held in the DMAC. Then, when activation is initiated in the DMAC, the
request is cleared, and
'5(4
pin high level sampling for edge detection is started. If
'5(4
pin
high level sampling has been completed by the time the DMA single cycle ends, acceptance
resumes after the end of the single cycle,
'5(4
pin low level sampling is performed again, and
this operation is repeated until the transfer ends.
'5(4
'5(4
'5(4
'5(4
Pin Low Level Activation Timing: Set the DTA bit in DMABCRH to 1 for the channel
for which the
'5(4
pin is selected.
Содержание H8S/2376 F-ZTAT
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