Freescale Semiconductor MCF52277 Reference Manual page 286

Enhanced Direct Memory Access (eDMA)
Field
15 Enables channel-to-channel linking on minor loop complete. As the channel completes the minor loop, this
E_LINK 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 TCDn_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.
14–13 Reserved, must be cleared.
12–9 Link channel number. If channel-to-channel linking is enabled (E_LINK = 1), then after the minor loop is
LINKCH exhausted, the eDMA engine initiates a channel service request at the channel defined by these four bits
by setting that channel's TCDn_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.
14–0 or Starting major iteration count. As the transfer control descriptor is first loaded by software, this 9-bit
8–0 (E_LINK = 1) or 15-bit (E_LINK = 0) field must be equal to the value in the CITER field. As the major
BITER 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.
Address: 0xFC04_501E + (0x20 × n) (TCDn_CSR)
15 14 13
R 0
BWC
W
Reset — — —
17-22
Table 17-29. TCDn_BITER Field Descriptions
Otherwise, a configuration error is reported. As the major iteration count is exhausted, the contents
of this field is reloaded into the 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.
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.
12 11 10 9
0
MAJOR_LINKCH
— — — —
Figure 17-28. TCDn Control and Status (TCDn_CSR)
MCF52277 Reference Manual, Rev. 1
Description
8 7 6 5
MAJOR_
DONE ACTIVE
E_LINK
— 0 0 —
Access: User read/write
4 3 2
INT_ INT_
E_SG D_REQ
HALF MAJOR
— — — —
Freescale Semiconductor
1 0
STAR
T
0