
Rev.1.30
Oct 06, 2004
page 70 of 249
M306V0ME-XXXFP, M306V0EEFP
Item
Specification
No. of channels
2 (cycle steal method)
Transfer memory space
From any address in the 1M bytes space to a fixed address
From a fixed address to any address in the 1M bytes space
From a fixed address to a fixed address
(Note that DMA-related registers [002016 to 003F16] cannot be accessed)
Maximum No. of bytes transferred
128K bytes (with 16-bit transfers) or 64K bytes (with 8-bit transfers)
DMA request factors (Note)
________
Falling edge or both edge of pin INT0
________
Falling edge of pin INT1
Timer A0 to timer A4 interrupt requests
Timer B0 to timer B2 interrupt requests
UART0 transmission and reception interrupt requests
UART2 transmission and reception interrupt requests
A-D conversion interrupt requests
OSD1 and OSD2 interrupt requests
Data slicer interrupt request
VSYNC interrupt request
Software triggers
Channel priority
DMA0 takes precedence if DMA0 and DMA1 requests are generated simultaneously
Transfer unit
8 bits or 16 bits
Transfer address direction
forward/fixed (forward direction cannot be specified for both source and
destination simultaneously)
Transfer mode
Single transfer mode
After the transfer counter underflows, the DMA enable bit turns to
“0”, and the DMAC turns inactive
Repeat transfer mode
After the transfer counter underflows, the value of the transfer counter reload register
is reloaded to the transfer counter.
The DMAC remains active unless a “0” is written to the DMA enable bit.
DMA interrupt request generation timing When an underflow occurs in the transfer counter
Active
When the DMA enable bit is set to “1”, the DMAC is active.
When the DMAC is active, data transfer starts every time a DMA
transfer request signal occurs.
Inactive
When the DMA enable bit is set to “0”, the DMAC is inactive.
After the transfer counter underflows in single transfer mode
Forward address pointer and
At the time of starting data transfer immediately after turning the DMAC active,
reload timing for transfer counter the value of one of source pointer and destination pointer - the one specified for the
forward direction - is reloaded to the forward direction address pointer, and the value
of the transfer counter reload register is reloaded to the transfer counter.
Writing to register
Registers specified for forward direction transfer are always write enabled.
Registers specified for fixed address transfer are write-enabled when
the DMA enable bit is “0”.
Reading the register
Can be read at any time.
However, when the DMA enable bit is “1”, reading the register set up as the
forward register is the same as reading the value of the forward address pointer.
Table 2.9.1 DMAC specifications
Note: DMA transfer is not effective to any interrupt. DMA transfer is affected neither by the interrupt enable
flag (I flag) nor by the interrupt priority level.