Dma Global Count Reload Register Used As Transfer Counter Reload - Texas Instruments TMS320C6201 Reference Manual

Transfer Counting
5.5 Transfer Counting
Figure 5–5. DMA Channel Transfer Counter Register
31
FRAME COUNT
Figure 5–6. DMA Global Count Reload Register Used As Transfer Counter Reload
31
FRAME COUNT RELOAD
5-16
The DMA channel transfer counter register, shown in Figure 5–5 contains
fields that represent the number of frames and the number of elements per
frame to be transferred. Figure 5–6 shows the DMA global count reload regis-
ter.
FRAME COUNT: The 16-bit unsigned value in this field sets the total number
of frames in the block transfer. The maximum number of frames per block trans-
fer is 65535. This counter is decremented upon the completion of the last read
transfer in a frame transfer. Once the last frame is transferred, the entire counter
is reloaded with the DMA controller global count reload register selected by the
CNT RELOAD field in the DMA channel primary control register (see section
5.4.1.1). Initial values of 0 and 1 in FRAME COUNT have the same effect of
transferring a single frame.
ELEMENT COUNT: The 16-bit unsigned value in this field sets the number of
elements per frame. This counter is decremented after the read transfer of
each element. The maximum number of elements per frame transfer is 65 535.
Once the last element in each frame is reached, ELEMENT COUNT is re-
loaded with the 16 LSBs of the DMA controller global count reload register se-
lected by the CNT RELOAD field in the DMA controller channel primary control
register. This reloading is unaffected by autoinitialization mode. Before a block
transfer begins, the counter and selected DMA controller global count reload reg-
ister must be loaded with the same 16 LSBs to assure that the first and remaining
frames have the same number of elements per frame. In any multiframe transfer,
a reload value must always be specified, not just when autoinitialization is en-
abled. If the element count is initialized as 0, operation is undefined.
RW, +0
RW, +0
16 15
ELEMENT COUNT
16 15
ELEMENT COUNT RELOAD
RW, +0
RW, +0
0
0