The modules TEI0015 and TEI0016 implements a handler for executing commands. The serial interface speed
must be set to 115200 bits, commands consists of a single  character in UTF-8 encoding.
Each command must be transmitted individually.

These commands apply since module revision 02.

"1"   Sets the pre-amplification of the ADC's input to 1

"2"   Sets the pre-amplification of the ADC's input to 2

"4"   Sets the pre-amplification of the ADC's input to 4

"8"   Sets the pre-amplification of the ADC's input to 8


"t"    The ADC measures 1 mega samples and saves the values into its SD-RAM

"x"    Instead of ADC values, the value "12345" is stored 1M times into its SD-RAM, values are transmitted via ".", "+" and "*"

"y"    Instead of ADC value, hexadecimal values, in ascending order, are generated and stored into the SD-RAM,
        the values are transmitted in via "." ,  "+" and "*"


"z"   The value "12345" is generated and direct transmitted 256 times

"r"    The ADC measure once and transmits this value


"."     A single value of stored ADC or generated measurement is transmitted

"+"   128 values of stored ADC or generated measurements are transmitted

"*"    16 kbit values of stored ADC or generated measurements are transmitted


"?"   The module returns its ID:
               TEI0015 with ADC AD4003 / 2 MSps returns "1"
               TEI0016 with ADC ADAQ7988 / 0.5 MSps returns "2"
               TEI0016 with ADC ADAQ7980 / 1 MSps returns "2"

"F"   The module activates a square wave signal,
        frequency = 10 kHz and  amplitude is +3,3 V / ground
        the signal is accessible on the pads
               - D5 in normal mode and
               - D6 in time inverted mode

"f"   Deactivation of the square wave signal


The following commands only apply to the TEI0016 - 1 MSps ADC variant, these commands have no effect on
TEI0016 - 0.5 MSps ADC or TEI0015 modules.

"a"   The sampling rate is set to 0.5 MSps

"b"  The sampling rate is set to 1 MSps