
TAMC900 User Manual Issue 2.0.1
Page 35 of 71
6.8 Channel DMA (Base) Descriptor Addresses 0-7
This register has two functions. On the one hand it holds an address into the embedded Block RAM (DMA
Descriptor Space). This defines the first descriptor to load out of the memory for a channel. Consequently, it
selects the first out of the three DMA descriptor instruction words. On the other hand it shows the Block RAM
address of the current processed descriptor.
Bit
Symbol
Description
Access
Reset
Value
31:26 -
Reserved
R
0
25:16 CADDR The pointer reflects the memory address of the current
loaded descriptor.
R 0
15:10 -
Reserved
R
0
9:0 BADDR
This address points into the memory where the channel
base address descriptor is placed.
R/W 0
Table 6-8 : Channel DMA (Base) Descriptor Address Register (Address 0x44+ 0x4*Channel)
6.9 Channel Pre-Trigger Data Size
In addition to the trigger mode that allows transmitting data before and after the trigger event this register is
used. The number of samples that are transmitted before the trigger event (pre-trigger data) is defined by the
register value.
Bit
Symbol Description
Access
Reset
Value
23:18 -
Reserved
R
0
17:0 NUM Number of samples that is transmitted via DMA as pre-
trigger data
R/W 0
Table 6-9 : Channel Pre-Trigger Data Register (Address 0x64+ 0x4*Channel)
Setting a value different then one requires that the number of samples has already been
acquired by the module. If this condition is violated, the obtained data will be invalid.