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GR716-DS-UM, May 2019, Version 1.29
266
www.cobham.com/gaisler
GR716
GPIO3: Cascade mode
GPIO4: Cascade mode and END
When enabled the sequencer starts with outputting the least significant bit of the GPIO selected as
END in the sequence.
The sequence output starts with outputting the least significant bit of the GPIO selected as END in the
sequence. In the example above the output sequence will be GPIO4.SEQDATA[0], ... ,GPIO4.SEQ-
DATA[31], GPIO3.SEQDATA[0], ... ,GPIO2.SEQDATA[31], GPIO2.SEQDATA[0], ...
,GPIO1.SEQDATA[31], GPIO1.SEQDATA[0], ... ,GPIO1.SEQDATA[31].
Cascading the sequencer memories are restricted to its neighbors and the START GPIO always has to
be selected to be at a lower GPIO index than the selected END GPIO.
The GPIOs included the cascade chain do not block its external ouput pin the external pin can be used
for other user functions. This is because the sequencer function is separated from the all other func-
tions including the general purpose IO.
29.5
Pulse sampler
GPIO inputs can be sampled and up to 32 states can be stored per input port. The sampler can be pro-
grammed to sample using internal trigger event and start when event is detected on the input. The
sampler can be enabled manually or by any of the interrupt requests on the APB bus. Samples will be
stored in the SAMPSEQ and interrupts can be optional generated at sample start or when SAMPSEQ
is full.
29.5.1 Operation modes
Sampler is enabled by setting the sampler enable bit in sequence control register 1. The sampling will
start if any of the following conditions are met:
•
Sample the state of the GPIO input when selected trigger event occur if the bit TR is set and bit
CT is set to 0 in sequence control register 1. (Repeated for every event until SAMPDATA is full)
•
A change in state on the input occur and the bit FD is set in sequence control register 1.
(Repeated for every event until SAMPDATA is full)
•
Consecutive sampling of the GPIO input until the register SAMPDATA is full.
Trigger and FD mode can be combined with the consecutive mode:
•
Sampling using combination of trigger and consecutive mode will start consecutive sampling of
the input when trigger event occurs until SAMPDATA is full.
•
Sampling using combination of FD and consecutive mode will start consecutive sampling of the
input when GPIO input state change occurs until SAMPDATA is full.
29.6
Registers
The core is programmed through registers mapped into APB address space.