Tcd Current Minor Loop Link, Major Loop Count (Channel Linking Disabled) (Dma_Tcdn_Citer_Elinkno) - STMicroelectronics SPC572L series Reference Manual

RM0400
Table 189. DMA_TCDn_CITER_ELINKYES field descriptions
Field
Enable channel-to-channel linking on minor-loop complete
As the channel completes the minor loop, this flag enables linking to another channel, defined by
the LINKCH field. The link target channel initiates a channel service request via an internal
mechanism that sets the TCDn_CSR[START] bit of the specified channel.
16
If channel linking is disabled, the CITER value is extended to 15 bits in place of a link channel
number. If the major loop is exhausted, this link mechanism is suppressed in favor of the
ELINK
MAJORELINK channel linking.
Note: This bit must be equal to the BITER[ELINK] bit. Otherwise, a configuration error is reported.
0 The channel-to-channel linking is disabled
1 The channel-to-channel linking is enabled
Link channel number
17–22
If channel-to-channel linking is enabled (ELINK = 1), then after the minor loop is exhausted, the
LINKCH eDMA engine initiates a channel service request to the channel defined by these six bits by
setting that channel's TCDn_CSR[START] bit.
Current major iteration count
This 9-bit (ELINK = 1) or 15-bit (ELINK = 0) count represents the current major loop count for the
channel. It is decremented each time the minor loop is completed and updated in the transfer
control descriptor memory. After the major iteration count is exhausted, the channel performs a
23–31
number of operations (e.g., final source and destination address calculations), optionally
generating an interrupt to signal channel completion before reloading the CITER field from the
CITER
beginning iteration count (BITER) field.
Note: When the CITER field is initially loaded by software, it must be set to the same value as that
19.3.27 TCD Current Minor Loop Link, Major Loop Count (Channel Linking
Disabled) (DMA_TCDn_CITER_ELINKNO)
See TCD Current Minor Loop Link, Major Loop Count (Channel Linking Disabled) register
figure and DMA_TCDn_CITER_ELINKNO field descriptions table as follows.
Address: FC0A_0000h base + 1014h offset + (32d × n), where n = 0d to 63d
0 1
R
W
(1)
Reset x x
Figure 145. TCD Current Minor Loop Link, Major Loop Count (Channel Linking Disabled)
1. x = Undefined at reset.
contained in the BITER field. If the channel is configured to execute a single service
request, the initial values of BITER and CITER should be 0x0001.
2 3 4 5
x x x x
(DMA_TCDn_CITER_ELINKNO)
DocID027809 Rev 4
Enhanced Direct Memory Access (eDMA)
Description
6 7 8 9
CITER
x x x x
Access: User read/write
10 11 12 13
x x x x
14 15
x x
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