Bruker DPP1 - Description

Description
Technical Manual Version 001 BRUKER BIOSPIN 47 (55)
Description
Next Gradient The Next Gradient appears before the Next Value that has changed
the gradient constant time acquisition. Before or directly afterward
the corresponding gradient packet is transferred, that is available at
the FIFO output at the Next Value after next. „Before“ means after
the previous Next Gradient gradient packet. „directly afterward“
means at the end of the following Next Value phase.
NG-Flag The Next Gradient is stored right before the next „Next Value“ flank
as „NG flag“. The NG flag is overwritten by the Next Value and
stored as „GF“ and „GFD“ until the next „Next Value“. The „GFD“ is
read as a status register bit from the DSP in the interrupt service
and marked with „logically-1“, the availability of a complete gradient
packet in FIFO. GF“ is always set by the „Next Value“ if a stored „NG
Flag“ exists. This means with a Next Value phase the GF and GFD
remain constantly on „1“.
GF:=NF-Flag;
GFD:=GF
INT, CALC Each „Next Value“ sets the INT interrupt signal to the DSP and the
CALC bit, which mark the computing phase of the DSP.
In the interrupt service the DSP reads the status of the GFD, puts
the INT bit back as promptly as possible, reads possible gradient
words from the input FIFO to the control word, counts and transfers
the calculated gradients words and the control word in the output
FIFO. Before leaving the service routine, as last action the CALC bit
is deleted.
When the CALC is set the „Next Value“ increments an error counter.
DSP + out-FIFO In this phase (when the GFD is set) the DSP reads in a gradient
block out of input FIFO, calculates it and writes the value in the out-
FIFO.
LVDS out Reads the output FIFO over the LVDS into the preload register of
the DAC‘s.
Control word The control word is the last word of a gradient packet in both FIFO‘s.
With the DPP1 the control word is transferred with the packet and is
used to control the gradient amplifier.
With the DPP (48-bit test version) the control word from the out-
FIFO serves only as a delimiter for the packets and is not trans
-
ferred with the packet to the gradient amplifier. The reason for this is
that the control word in the BGU leads to the deletion of the register.