Texas Instruments Tiva TM4C123GH6PM, User Manual

Page: 280 / 352

uDMA Controller
Parameters:
ui32ChannelStructIndex is the logical OR of the uDMA channel number with
UDMA_PRI_SELECT or UDMA_ALT_SELECT .
ui32Control is logical OR of several control values to set the control parameters for the chan-
nel.
Description:
This function is used to set control parameters for a uDMA transfer. These are typically param-
eters that are not changed often.
The ui32ChannelStructIndex parameter should be the logical OR of the channel number with
one of UDMA_PRI_SELECT or UDMA_ALT_SELECT to choose whether the primary or alter-
nate data structure is used.
The ui32Control parameter is the logical OR of five values: the data size, the source address
increment, the destination address increment, the arbitration size, and the use burst flag. The
choices available for each of these values is described below.
Choose the data size from one of UDMA_SIZE_8 , UDMA_SIZE_16 , or UDMA_SIZE_32 to
select a data size of 8, 16, or 32 bits.
Choose the source address increment from one of UDMA_SRC_INC_8 ,
UDMA_SRC_INC_16 , UDMA_SRC_INC_32 , or UDMA_SRC_INC_NONE to select an
address increment of 8-bit bytes, 16-bit halfwords, 32-bit words, or to select non-incrementing.
Choose the destination address increment from one of UDMA_DST_INC_8 ,
UDMA_DST_INC_16 , UDMA_DST_INC_32 , or UDMA_DST_INC_NONE to select an
address increment of 8-bit bytes, 16-bit halfwords, 32-bit words, or to select non-incrementing.
The arbitration size determines how many items are transferred before the uDMA controller re-
arbitrates for the bus. Choose the arbitration size from one of
UDMA_ARB_1 , UDMA_ARB_2 ,
UDMA_ARB_4 , UDMA_ARB_8 , through UDMA_ARB_1024 to select the arbitration size from
1 to 1024 items, in powers of 2.
The value
UDMA_NEXT_USEBURST
is used to force the channel to only respond to burst
requests at the tail end of a scatter-gather transfer.
Note:
The address increment cannot be smaller than the data size.
Returns:
None.
23.2.1.6 ROM_uDMAChannelDisable
Disables a uDMA channel for operation.
Prototype:
void
ROM_uDMAChannelDisable(uint32_t ui32ChannelNum)
ROM Location:
ROM_APITABLE
is an array of pointers located at
0x0100.0010
.
ROM_UDMATABLE
is an array of pointers located at
ROM_APITABLE[17]
.
ROM_uDMAChannelDisable
is a function pointer located at
ROM_UDMATABLE[6]
.
280 April 8, 2013