Spectrum Brands MI.61XX 用户手册

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MI.61xx Manual

Programming

FIFO Mode

When using FIFO mode together with one of the options that allow to have gaps in the generation like Multiple Replay or Gated Replay one 
can even run the board with higher sample rates. It just has to be sure that the average sample rate (calculated with generation time and 
gap) does not exceed the above mentioned sample rate limitations.

The sample rate that can be run in one of these mode is depending on the number of channels that have been activated. Due to the internal 
structure of the board this is limited to a internal throughput of 250 MB/s (250 MS/s):

 

The setup of FIFO mode is done with a few additional software registers described in this chapter. All the other settings can be used as des-
cribed before. In FIFO mode the register SPC_MEMSIZE and SPC_POSTTRIGGER are not used.

This register defines the number of software buffers that should be used for FIFO mode. The number of hardware buffers is always two and 
can not be changed by software.

When this manual was printed there are a total of 256 buffers possible. However if there are changes and enhancements to the driver in the 
future it will be informative to read out the number of buffers the new driver version can hold.

The length of each buffer is defined in bytes. This length is used for hardware and software buffers as well. Both have the same length. The 
maximum length that can be used is depending on the installed on-board memory.

Each FIFO buffer can be a maximum of half the memory. Be aware that the buffer length is given in overall bytes not in samples. Therefore 
the value has to be calculated depending on the activated channels and the resolution of the board:

1 Channel

100 MS/s

[1 Channel] x [1 Byte per sample] * 100 MS/s = 100 MB/s

2 Channels

50 MS/s

[2 Channels] x [1 Byte per sample] * 50 MS/s = 100 MB/s

4 Channels

25 MS/s

[4 Channels] x [1 Byte per sample] * 25 MS/s = 100 MB/s

8 Channels

12.5 MS/s

[8 Channels] x [1 Byte per sample] * 12.5 MS/s = 100 MB/s

1 Channel

250 MS/s

[1 Channel] x [1 Byte per sample] x 250 MS/s = 250 MB/s

2 Channels

125 MS/s

[2 Channels] x [1 Byte per sample] x 125 MS/s = 250 MB/s

4 Channels

62.5 MS/s

[4 Channels] x [1 Byte per sample] x 62.5 MS/s = 250 MB/s

8 Channels

31.25 MS/s

[8 Channels] x [1 Byte per sample] x 31.25 MS/s = 250 MB/s

SPC_FIFO_BUFFERS

60000

r/w

Number of software buffers to be used for FIFO mode. Value has to be between 2 and 256

SPC_FIFO_BUFADRCNT

60040

r

Read out the number of available FIFO buffers

SPC_FIFO_BUFLEN

60010

r/w

Length of each buffer in bytes. Must be a multiple of 1024 bytes.