SPI BUS Serial Decode Option for the DS4000 Oscilloscope. Requires a 4 channel scope.

SPI Decoding (Option)

SPI serial bus consists of chip select line (SS), clock line (SCLK), MISO and MOSI.

SS: set the polarity to “Low” or “High”. When SS selection is valid, the SPI bus samples data from MISO and MOSI at the jumping point of SCLK.
SCLK: sample data from MISO and MOSI on the clock rising edge or falling edge.
MISO: master input/slave output. Set the polarity to “Low” or “High”.
MOSI: master output/slave input. Set the polarity to “Low” or “High”.

Press Decode1 → Decode to select “SPI” and open the SPI decoding function menu.

1. SS Setting

Press SS to turn the chip select line setting interface on.

• Press Channel to select any channel (CH1 to CH4) as the chip select channel. When “OFF” is selected, the sample of MISO and MOSI occurs at the jumping point of SCLK.
• Press Polarity to set the polarity of the chip select channel to “Low” or“High”.
• Press Threshold to set the threshold of the selected channel.

2. SCLK Setting

 Press SCLK to turn on the clock line setting interface.

• Press Channel to select any channel (CH1 to CH4) as the clock channel.
• Press Slope to set the instrument to sample MISO and MOSI on the rising edge or falling edge of SCLK.
• Press Threshold to set the threshold of the clock channel.

3. MISO Setting
    Press MISO to enter the MISO data line setting interface.

• Press Channel to select any channel (CH1 to CH4) as the MISO data channel. When “OFF” is selected, this data line is not set.
• Press Polarity to set the polarity of the MISO data line to “Low” or “High”.
• Press Threshold to set the threshold of the MISO data channel.

5. Data Bits Setting

Press Data Bits to set the number of bits of each frame of data. The range available is from 4 to 32.

6. Endian Setting    

Press Endian to select “LSB” or “MSB” and the default is “MSB”.

7. Display-related Setting

Press Format to set the display format of the bus to Hex, Decimal, Binary or ASCII.

Press Offset and use to  adjust the vertical display position of the bus.

Press BusStatus to turn the bus display on or off.

8. Decoding Table

The decoding table displays the decoded data, the corresponding time and error information on the MOSI or MISO data line in table format. It can be used to observe relatively longer decoded data to solve the problem that some data could not be seen clearly on the screen.

Press Event Table → Event Table to select “ON” (note that this operation is only available when BusStatus is set to “ON”) to enter the decoding table interface as shown in the figure below. If an USB storage device is currently connected to the instrument, press Export to export the data table to the

external USB storage device in CSV format.

9. Error Expressions during Decoding

When the clock for a frame in SPI is nout enough, the data is filled with red patches. For example, when Data Bits is set to 7 and SCLK slope is set to rising edge, decoding error will be generated.