CHAPTER 6 DMA FUNCTIONS (DMA CONTROLLER)
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User’s Manual U14359EJ4V0UM
6.3.5 DMA channel control registers 0 to 3 (DCHC0 to DCHC3)
These 8-bit registers are used to control the DMA transfer operating mode for DMA channel n (n = 0 to 3).
These registers can be read/written in 8-bit or 1-bit units. (However, bit 7 is read only and bits 2 and 1 are write
only. If bits 2 and 1 are read, the read value is always 0.)
Address
FFFFF0E0H
<7>
TC0
DCHC0
6
0
5
0
4
0
<3>
MLE0
<2>
INIT0
<1>
STG0
<0>
E00
After reset
00H
FFFFF0E2H
TC1
DCHC1
0
0
0
MLE1
INIT1
STG1
E11
00H
FFFFF0E4H
TC2
DCHC2
0
0
0
MLE2
INIT2
STG2
E22
00H
FFFFF0E6H
TC3
DCHC3
0
0
0
MLE3
INIT3
STG3
E33
00H
Bit position
Bit name
Function
7
TCn
(n = 0 to 3)
Terminal Count
This status bit indicates whether DMA transfer through DMA channel n has ended or not.
This bit is read-only. It is set to 1 when DMA transfer ends and cleared (to 0) when it is
read.
0: DMA transfer has not ended.
1: DMA transfer has ended.
3
MLEn
(n = 0 to 3)
Multi Link Enable Bit
When this bit is set to 1 at terminal count output, the Enn bit is not cleared to 0 and the
DMA transfer enable state is retained. Moreover, the next DMA transfer request can be
acknowledged even when the TCn bit is not read.
When this bit is cleared to 0 at terminal count output, the Enn bit is cleared to 0 and the
DMA transfer disable state is entered. At the next DMA request, the Enn bit must be set to
1 and the TCn bit read.
Cautions 1. The MLEn bit is valid when DMA transfer is started by the DMARQn
signal or by an interrupt from the on-chip peripheral I/O.
2. To start DMA transfer by software by setting the STGn bit to 1, be sure
to read the TCn bit and then set the STGn bit to 1 even if the MLEn bit
is set to 1.
2
INITn
(n = 0 to 3)
Initialize
When this bit is set to 1, DMA transfer is forcibly terminated.
1
STGn
(n = 0 to 3)
Software Trigger
If this bit is set to 1 in the DMA transfer enable state (TCn bit = 0, Enn bit = 1), DMA
transfer is started.
0
Enn
(n = 0 to 3)
Enable
Specifies whether DMA transfer through DMA channel n is to be enabled or disabled. This
bit is cleared to 0 when DMA transfer ends. It is also cleared to 0 when DMA transfer is
forcibly terminated by setting the INITn bit to 1 or by NMI input.
0: DMA transfer disabled
1: DMA transfer enabled