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Enhanced Direct Memory Access (eDMA)
19-20
Freescale Semiconductor
Table 19-25. TCD
n
_DADDR Field Descriptions
Field
Description
31–0
DADDR
Destination address. Memory address pointing to the destination data.
Address: 0xFC0 (0x20
n
) (TCD
n
_CITER)
Access: User read/write
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
E_LINK = 1
R
E_LINK
0
0
LINKCH
CITER
W
E_LINK = 0
R
E_LINK
CITER
W
Reset
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Figure 19-24. TCD
n
Current Major Iteration Count (TCD
n
_CITER)
Table 19-26. TCD
n
_CITER Field Descriptions
Field
Description
15
E_LINK
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 TCD
n
_CSR[START] bit of the specified
channel.
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 MAJOR_E_LINK channel
linking.
0 The channel-to-channel linking is disabled.
1 The channel-to-channel linking is enabled.
Note:
This bit must be equal to the BITER.E_LINK bit. Otherwise, a configuration error is reported.
14–13
Reserved, must be cleared.
12–9
LINKCH
Link channel number. If channel-to-channel linking is enabled (E_LINK = 1), then after the minor loop is
exhausted, the eDMA engine initiates a channel service request to the channel defined by these four bits
by setting that channel’s TCD
n
_CSR[START] bit.
0–15 Link to DMA channel 0–15
14–0 or
8–0
CITER
Current major iteration count. This 9-bit (E_LINK = 1) or 15-bit (E_LINK = 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 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 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
contained in the BITER field.
Note:
If the channel is configured to execute a single service request, the initial values of BITER and CITER
should be 0x0001.
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...