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Section 14 Direct Memory Access Controller (DMAC)
SH7751 Group, SH7751R Group
Page 522 of 1128
R01UH0457EJ0301 Rev. 3.01
Sep 24, 2013
On-Chip Peripheral Module Request Mode:
In this mode a transfer is performed in response to
a transfer request signal (interrupt request signal) from an on-chip peripheral module. As shown in
table 14.5, there are seven transfer request signals: input capture interrupts from the timer unit
(TMU), and receive-data-full interrupts (RXI) and transmit-data-empty interrupts (TXI) from the
two serial communication interfaces (SCI, SCIF). If DMA transfer is enabled (DE = 1, DME = 1,
TE = 0, NMIF = 0, AE = 0), transfer starts when a transfer request signal is input.
The source of the transfer request does not have to be the data transfer source or destination.
However, when the transfer request is set to RXI (transfer request by SCI/SCIF receive-data-full
interrupt), the transfer source must be the SCI/SCIF's receive data register (SCRDR1/SCFRDR2).
When the transfer request is set to TXI (transfer request by SCI/SCIF transmit-data-empty
interrupt), the transfer destination must be the SCI/SCIF's transmit data register
(SCTDR1/SCFTDR2).
Table 14.5 Selecting On-Chip Peripheral Module Request Mode with RS Bits
RS3
RS2
RS1
RS0
DMAC Transfer
Request Source
DMAC Transfer
Request Signal
Transfer
Source
Transfer
Destination Bus Mode
1 0 0 0 SCI
transmitter
SCTDR1
(SCI
transmit-data-
empty transfer
request)
External
*
SCTDR1 Cycle
steal
mode
1
SCI
receiver SCRDR1
(SCI
receive-data-full
transfer request)
SCRDR1 External
*
Cycle
steal
mode
1 0 SCIF
transmitter
SCFTDR2
(SCIF
transmit-data-
empty transfer
request)
External
*
SCFTDR2 Cycle
steal
mode
1
SCIF
receiver
SCFRDR2
(SCIF
receive-data-full
transfer request)
SCFRDR2 External
*
Cycle
steal
mode
1 0 0 TMU
channel
2
Input
capture
occurrence
External
*
External
*
Burst/cycle
steal mode
1
TMU channel 2
Input capture
occurrence
External
*
On-chip
peripheral
Burst/cycle
steal mode
1
0
TMU channel 2
Input capture
occurrence
On-chip
peripheral
External
*
Burst/cycle
steal mode
Legend:
TMU: Timer
unit
SCI:
Serial communication interface
SCIF: Serial communication interface with FIFO