185
Bit 3: TS
Description
0
Byte (8 bits)
(Initial value)
1
Word (16 bits)
•
Bit 2 (Interrupt Enable Bit (IE)): IE determines whether or not to request a CPU interrupt at the
end of a DMA transfer. When the IE bit is set to 1, an interrupt (DEI) request is sent to the
CPU when the TE bit is set. The IE bit is initialized to 0 by a reset and in standby mode.
Bit 2: IE
Description
0
Interrupt request disabled
(Initial value)
1
Interrupt request enabled
•
Bit 1 (Transfer End Flag Bit (TE)): TE indicates that the transfer has ended. When a DMA
transfer ends normally and the value in the DMA transfer count register (TCR) becomes 0, the
TE bit is set to 1. This flag is not set if the transfer ends because of an NMI interrupt or address
error, or because the DE bit or the DME bit in the DMA operation register (DMAOR) was
cleared. To clear the TE bit, read 1 from it and then write 0.
When this flag is set, setting the DE bit to 1 does not enable a DMA transfer. The TE bit is
initialized to 0 by a reset and in standby mode.
Bit 1: TE
Description
0
DMA has not ended or was aborted
(Initial value)
To clear TE, the CPU must read TE after it has been set to 1, then
write a 0 in this bit
1
DMA has ended normally
•
Bit 0 (DMA Enable Bit (DE)): DE enables or disables DMA transfers. In auto-request mode,
the transfer starts when this bit or the DME bit in DMAOR is set to 1. The TE bit and the
NMIF and AE bits in DMAOR must be all cleared to 0. In external request mode or on-chip
supporting module request mode, the transfer begins when the DMA transfer request is
received from a device or on-chip supporting module, provided this bit and the DME bit are set
to 1. As with auto request mode, the TE bit and the NMIF and AE bits must be all cleared to 0.
The transfer can be stopped by clearing this bit to 0.
The DE bit is initialized to 0 by a reset and in standby mode.
Содержание HD6417032
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Страница 525: ...490 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 18 Self Refresh ...
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