mempeek
(To be removed) Low-level memory read from VXI register
This visa
object function will be removed in a future release. Use
visadev
object functions instead. For more information, see Compatibility Considerations.
Syntax
out = mempeek(obj,offset)
out = mempeek(obj,offset,'precision
')
Arguments
| A VISA-VXI or VISA-GPIB-VXI object. |
| The offset in the mapped memory space from which the data is read. |
| The number of bits to read from the memory address. |
| An array containing the returned value. |
Description
out = mempeek(obj,offset)
reads a
uint8
value from the mapped memory space specified by
offset
for the object obj
. The value is
returned to out
.
out = mempeek(obj,offset,'
reads the number of bits specified by precision
')precision
, from the
mapped memory space specified by offset
.
precision
can be uint8
,
uint16
, or uint32
, which instructs
mempeek
to read 8-, 16-, or 32-bit values, respectively.
precision
can also be single
,
which instructs mempeek
to read single precision values.
Examples
Create the VISA-VXI object vv
associated with a VXI chassis
with index 0, and a Keysight® E1432A digitizer with logical address 130.
vv = visa('keysight','VXI0::130::INSTR'); fopen(vv)
Use memmap
to map 16 bytes in the A16 address space.
memmap(vv,'A16',0,16)
Perform a low-level read of the first and second instrument registers.
reg1 = mempeek(vv,0,'uint16') reg1 = 53247 reg2 = mempeek(vv,2,'uint16') reg2 = 20993
Unmap the memory and disconnect vv
from the instrument.
memunmap(vv) fclose(vv)
Tips
Before you can read from the VXI register, obj
must be
connected to the instrument with the fopen
function. A connected
interface object has a Status
property value of
open
. An error is returned if you attempt a read operation
while obj
is not connected to the instrument.
You must map the memory space using the memmap
function before using
mempeek
. The
MappedMemorySize
property returns the size of the memory
space mapped.
offset
indicates the offset in the mapped memory space from
which the data is read. For example, if the mapped memory space begins at 200H, the
offset is 2, and the precision is uint8
, then the data is read
from memory location 202H. If the precision is uint16
, the data
is read from 202H and 203H.
To increase speed, mempeek
does not return error
messages from the instrument.
Version History
Introduced before R2006aSee Also
fopen
| memmap
| mempoke
| memunmap
| MappedMemorySize | MemoryIncrement