I2C Signal Properties

Use the I2C Signal type to decode two channels using the full I2C serial protocol.

Signal Name

Change the text displayed here to help you identify this signal definition. If the name has already been used, it will automatically be appended with a numerical value in brackets (i.e. [2]). The name displayed here will be used in the Waveform Views, Searches, Tables, Lists, Exports and all menu references.

Color Selection & Examples

An example is displayed in the current color scheme, followed by a listing of any items that allow custom colors (i.e. Signal Color, Signal Background). Click on an item in the list to select a new color.

Clock (SCL)

Selects which physical channel to assign to the CLOCK.

Data (SDA)

Selects which physical channel to assign to the DATA bus.

Glitch Filter

Selects the amount of noise filtering.   Should be set to 50ns for low speed buses and reduces for FAST buses.

Skip Bits (to sync partial frame)

Specifies how many bits to ignore at the start of the buffer. Useful for syncing up when capture starts mid-frame.

Decode Addr 000-0001-d as

Selects between the standard I2C decoding for this address range or decoding it as normal 7 bit devices.

Decode Addr 000-001X-d as

Selects between the standard I2C decoding for this address range or decoding it as normal 7 bit devices.

Decode Addr 111-11XX-d as

Selects between the standard I2C decoding for this address range or decoding it as normal 7 bit devices.

Decode HS Master Codes as

Selects between the standard I2C decoding for this address range or decoding it as normal 7 bit devices.

Decode 10bit Codes as

Selects between the standard I2C decoding for this address range or decoding it as normal 7 bit devices.

Truncated fields

Specified whether to show truncated/partial fields or not.  1 bit truncated fields common and unavoidable so the options include showing only if > 1 bit.

Show ACKs

Selects whether to show ACKs in the waveforms, tables and searches NAKs are always shown.

Show Addresses as

The I2C spec defines 7 bit addresses and a 1 bit direction (R/W) in teh first field. Sometimes it is convenient to think of this as a single 8 bit value.  This option specifies whether to show as 2 fields (per spec.) or as a single 8 bit field.

Show IDLEs

Specifies whether idle time between fields should be shown as a hashed field or if the current field should just extend to the next field.

Channel Selection

This is where you will associate a signal definition with the physical channels or connections to the outside world. Each signal definition type will have one or more channel selection groups and will allow one or more channels to be selected for each group. Each channel selection group will be identified on its left if more than one group is available for the signal type.

To select a channel, click on the " - " below the proper color (and channel number) that corresponds to the physical connection of the DigiView Cable (see: Connecting the Data Lines). Channels that are selected for this signal will replace the " - " with a blue "dot" as shown above. Channels that are already defined in other signal definitions will have a darker color around the selection area for the channel (as channels 1 and 2 do in the graphic above).

Reset Colors

This button will reset the colors for this signal so that they will match the currently selected color theme (see: Color Themes).

Display Fields

Start

Field type used to show start and repeated start event.

Shows ' S ' for start or ' Sr ' for repeated start.

Stop

Field type used for stop events.  Shows ' P '.

Addr

Field type used for normal 7bit address fields

Addr8

Field type used to show first byte as 8 bit address+direction

Data

Field type used for most characters.  Shows the received byte

Ack

Field type used to show Acknoledge bit.  Shows ' A '

Nak

Field type used to show Nak bits.  Shows ' N '.

WRITE

Field type used to show WRITE bits.  Shows ' W '.

READ

Field type used to show READ bits.  Shows ' R '.

General-Call

Field type used to show first byte code is General-Call.

Shows ' Gen-Call '

Start-Byte

Field type used whenthe first byte code is START BYTE.

Shows ' START '.

HS Master

Field type used when first byte code is High Speed Master.

Shows ' HS Master: ' followd by the 3 bit master ID

CBUS

Field type used when the first byte code is CBUS.

Prints the word CBUS.

Reserved

Field type used when the first byte is a reserved address.

Prints the word  'RESERVED: ' followed by the actual data

10bitMode

Field type used when the first byte code is 10 bit Mode.

Prints ' 10bitMode: ' followed by the high 2 bits of the 10bit address.

Truncated

Field type used when a byte is truncated (bt a stop or repeated start)

Prints ' T: ' followed by the received data.