Rohde Schwarz Rohde & Schwarz HMO1002 2-channel oscilloscope, Digital Storage oscilloscope, 21-1002-RS00 데이터 시트

the bottom of the screen. Generally, a complete message 
of a protocol is displayed in a row. The columns include 
important information, e.g. address and date of the mes-
sage. The number of rows in the table is identical to the 
number of complete message frames in storage. The de-
coding results may be saved as CSV file by using the soft
menu key SAVE (e.g. save to a USB stick).

“Bus table: BUS1 (I2C: Clock SCL = D0, Dates SDA = D1)“
Frame,Mark,Start time[s],Type,ID,Length,Date,Condition
1,,-197.89200e-6,Read,0x2D,5,0xF110E55D31,OK
2,,28.00000e-9,Write,0x42,8,0xEB8DC599AE5D6FC0,OK
3,,217.74000e-6,Write,0x3B,6,0xA113B7263E5B,OK
4,,376.07200e-6,Read,0x0E,6,0x55C3EB71D9E8,OK
5,,613.58000e-6,Write,0x66,8,0x91B86EE6655E2300,Data 
Error0

The soft menu key TRACK FRAME allows you to scroll 
through the BUS table and simultaneously jump to the
corresponding position in the memory via universal knob 
to display details on the screen. However, this is only pos-
sible if acquisition has been stopped. This option is also 
available in the short menu BUS via soft menu key TRK 
(= Track). If you activate the soft menu key FRAME TIME 
DIFFERENCE (highlighted in blue), the time difference to 
the previous frame (data packet) will be displayed in the 
BUS table. This column will be labeled in the table as TIME 
DIFF. If this function is deactivated, the absolute time in 
relation to the trigger point will be displayed in the column 
START TIME. The soft menu key Tab in the BUS short 
menu allows you to activate or deactivate the BUS table 
without opening a menu. You can use the soft menu item 
POSITION to move the table to the top or bottom of the 
screen. In addition, it is possible to display the BUS table 
in full screen. Select the position via universal knob in the 
BUS menu or directly via soft menu key Pos in the BUS 
short menu.

Fig. 13.2: Example I

2

C BUS with BUS table

The R&S®HMO1002 has a PARALLEL and PARALLEL 
CLOCKED BUS function installed ex factory and is able to 
analyze up to 7 bit lines. The soft menu key BUS WIDTH 
and the universal knob allow you to select the number 
of bit lines. The soft menu keys PREVIOUS/NEXT BIT al-
low you to move the position of the selection bar for the 
source of the individual bits. The selected bit is highlighted 
in blue. The left side of the table contains the bits in fixed
sequence, beginning at the top with D0 (= LSB). The uni-
versal knob allows you to assign a real logic channel to the 
selected BUS bit. The allocation is not subject to restric-
tions; you can also use partially identical logic channels in 
the two possible buses. If you select PARALLEL CLOCKED 
as BUS TYPE, you can also use the bottom soft menu key 
CONTROL WIRES to select sources for CHIP SELECT, and 
you can use the universal knob to select the settings for 
CLOCK. The soft menu key ACTIVE is used to determine if 
the chip select signal High or Low Active is selected.

The soft menu key SLOPE allows you to toggle between ri-
sing, falling and both slopes. The active selection is always 
highlighted in blue and is listed after the label CLK in the 
bit source window. Press the MENU OFF button to return 
to the BUS main menu. 

To trigger on parallel buses, it is recommended to use the 
logic trigger (see chapter 6.3.3).

The I

2

C BUS is a two-wire bus which was developed by 

Philips (today known as NXP Semiconductor). A I

2

C BUS 

has the following properties:

 ❙Two wire bus (2-wire): Clock (SCL) and data (SDA)
 ❙Master-Slave Communication: the master provides the 

clock pulse and selects the slave

 ❙Addressing: Each slave can be addressed via unique 

address; multiple slaves can be linked with each other and 
can be addressed by the same master

 ❙Read/Write bit: Master reads data (=1) or writes data (=0)
 ❙Acknowledge: issued after each byte

The format of a simple I

2

C message (frame) with an 

address length of 7 bit is structured as follows: 

 ❙Start condition: Falling slope on SDA (Serial Data), while 

SCL (Serial Clock) is HIGH

 ❙7 bit address (write or read slave)

Fig. 13.3: I

2

C 7-Bit-Adress