Example 1: reading the firmware version from Register 9

Output Data

Byte 0: Control byte

Byte 1: DataOUT1, high byte

Byte 2: DataOUT1, low byte

0x89 (1000 1001bin)

0xXX

0xXX

Explanation:

  • Bit 0.7 set means: Register communication switched on.
  • Bit 0.6 not set means: reading the register.
  • Bits 0.5 to 0.0 specify the register number 9 with 00 1001bin.
  • The output data word (byte 1 and byte 2) has no meaning during read access. To change a register, write the required value into the output word.

Input Data (answer of the Bus Terminal)

Byte 0: Status byte

Byte 1: DataIN1, high byte

Byte 2: DataIN1, low byte

0x89

0x33

0x41

Explanation:

  • The terminal returns the value of the control byte as a receipt in the status byte.
  • The terminal returns the firmware version 0x3341 in the input data word (byte 1 and byte 2). This is to be interpreted as an ASCII code:
    • ASCII code 0x33 represents the digit 3
    • ASCII code 0x41 represents the letter A
      The firmware version is thus 3A.