AX−SFUS, AX−SFUS−API

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14

Table 10. COMMANDS

Command

Description

Name

AT:ADC Pn[−Pn[ (1V|10V)]]?

Get GPIO Pin Analog Voltage

Measure the voltage applied to a GPIO pin. The command also

allows measurement of the voltage difference across two GPIO pins.

In differential mode, the full scale range may also be specified as 1 V

or 10 V. Note however that the pin input voltages must not exceed

the range 0..VDD_IO. The command returns the result as fraction of

the full scale range (1 V if none is specified). The GPIO pins

referenced should be initialized to analog mode before issuing this

command.

AT:SPI[(A|B|C|D)]=bytes

SPI Transaction

This command clocks out bytes on the SPI port. The clock frequency is

312.5 kHz. The command returns the bytes read on MISO during out-

put. Optionally the clocking mode may be specified (default is A):

Mode

Clock Inversion

Clock Phase

A

normal

normal

B

normal

alternate

C

inverted

normal

D

inverted

alternate

Note that SEL, if needed, is not generated by this command,

and must instead be driven using standard GPIO commands

(AT:Pn=0|1).

AT:CLK=freq,reffreq

Set Clock Generator

Output a square wave on the pin(s) set to T mode. The frequency of

× reffreq. Possible values for reffreq

are 20000000, 10000000, 5000000, 2500000, 1250000, 625000,

312500, 156250. Possible values if freq are 0

…65535.

AT:CLK=OFF

Turn off Clock Generator

Switch off the clock generator

AT:CLK?

Get Clock Generator

Return the settings of the clock generator. Two numbers are

returned, freq and reffreq.

AT:DAC=value

Set

SD DAC

Output a

SD DAC value on the pin(s) set to T mode. Parameter

value may be in the range −32768

…32767. The average output

× VDD.

An external low pass filter is needed to get smooth output voltages.

The modulation frequency is 20 MHz. A possible low pass filter

choice is a simple RC low pass filter with R = 10 k

W and C = 1 mF.

AT:DAC=OFF

Turn off

SD DAC

Switch off the DAC

AT:DAC?

Get

SD DAC

Return the DAC value