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Enhanced Direct Memory Access (eDMA)
19-22
Freescale Semiconductor
Table 19-29. TCD
n
_BITER Field Descriptions
Field
Description
15
E_LINK
Enables channel-to-channel linking on minor loop complete. As the channel completes the minor loop, this
flag enables the linking to another channel, defined by BITER.LINKCH. 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 disables, the BITER value extends 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:
When the software loads the TCD, this field must be set equal to the corresponding CITER field.
Otherwise, a configuration error is reported. As the major iteration count is exhausted, the contents
of this field is reloaded into the CITER field.
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 at 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
Note:
When the software loads the TCD, this field must be set equal to the corresponding CITER field.
Otherwise, a configuration error is reported. As the major iteration count is exhausted, the contents
of this field is reloaded into the CITER field.
14–0 or
8–0
BITER
Starting major iteration count. As the transfer control descriptor is first loaded by software, this 9-bit
(E_LINK = 1) or 15-bit (E_LINK = 0) field must be equal to the value in the CITER field. As the major
iteration count is exhausted, the contents of this field are reloaded into the CITER field.
Note:
When the software loads the TCD, this field must be set equal to the corresponding CITER field.
Otherwise, a configuration error is reported. As the major iteration count is exhausted, the contents
of this field is reloaded into the CITER field. If the channel is configured to execute a single service
request, the initial values of BITER and CITER should be 0x0001.
Address: 0xFC0 (0x20
n
) (TCD
n
_CSR)
Access: User read/write
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R
BWC
0
0
MAJOR_LINKCH
DONE ACTIVE
MAJOR_
E_LINK
E_SG D_REQ
INT_
HALF
INT_
MAJOR
START
W
Reset
—
—
—
—
—
—
—
—
0
0
—
—
—
—
—
0
Figure 19-28. TCD
n
Control and Status (TCD
n
_CSR)
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 ...