The modules TEI0015, TEI0016 and TEI0023 implement 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.


All commands are identical for all tree modules, except commands for setting the gain.


The modules TEI0015 and TEI0016 recognizes the following gain commands 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


The following gain commands are recognized by all TEI0023 modules in every module revision:


"0" Deactivates the pre-amplifier

"1" Sets the pre-amplification of the ADC's input to 0.25

"2" Sets the pre-amplification of the ADC's input to 0.5

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

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

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

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

"8" Sets the pre-amplification of the ADC's input to 16


The modules TEI0015 and TEI0023 have an ADC with additional features since revision 02 for TEI0015 and revision 03 for TEI0023:


"S" Activates the Input Span Compression
"s" Deactivates the Input Span Compression

"H" Activates the High-Z Mode
"h" Deactivates the High-Z Mode


These commands are recognized by every module:


"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"
               TEI0016-0x-08-C8A with ADC ADAQ7988 / 0.5 MSps returns "2"
               TEI0016-0x-08-C8B with ADC ADAQ7980 / 1 MSps returns "3"
               TEI0023A with ADC AD4003 / 2 MSps returns "4"

"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