CC2510Fx / CC2511Fx
The behavior of each of the five DMA
channels is configured with the following
parameters:
Note: For byte size transfers (see Section
12.5.2.4), n is defined as the first byte in
source data or the 7 LSB of the first byte in
source data, depending on the M8 setting
(see Section 12.5.2.9). For word size
transfers, n is the 13 LSB of the first word
in source data.
12.5.2.1 Source Address (SRCADDR)
The address of the location in XDATA memory
space where the DMA channel shall start to
read data.
There are four possible configurations:
1. VLEN=001
12.5.2.2 Destination Address (DESTADDR)
Transfer
number
commanded by n + 1
of
of
of
of
bytes/words
bytes/words
bytes/words
bytes/words
The address of the location in XDATA memory
space where the DMA channel will write the
data read from the source address. The user
must ensure that the destination is writable.
2. VLEN=010
Transfer
number
commanded by n
12.5.2.3 Transfer Count
3. VLEN=011
The number of bytes/words needed to be
moved from source to destination. When the
transfer count is reached, the DMA controller
rearms or disarms the DMA channel
(depending on transfer mode) and alert the
CPU by setting the DMAIRQ.DMAIFn bit to 1.
If IRQMASK=1, IRCON.DMAIF will also be set
and an interrupt request is generated if
IEN1.DMAIE=1. The transfer count can be of
fixed or variable length depending on how the
DMA channel is configured.
Transfer
number
commanded by n + 2
4. VLEN=100
Transfer
number
commanded by n + 3
For all of the above configurations, the transfer
count will be limited to LEN bytes/words when
n ≥ LEN. In cases where n < LEN, the transfer
count is given by the VLENsetting. This means
that when VLEN=010, LEN should be equal to
Fixed Length Transfer Count: When
VLEN=000or VLEN=111, the transfer count is
set by the LENsetting.
n
max, while in the other three cases, LEN
should be set to nmax + 1.
Note that the M8 bit is only used when byte
size transfers are chosen.
Variable Length Transfer Count: When
VLEN≠000 and VLEN≠111, the transfer count
is given by the value of the first byte/word in
source data, n, + a constant given by the
VLEN setting. This allows for variable length
transfer count.
Figure 27 shows the different VLENoptions.
SWRS055F
Page 100 of 241
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