WB_I2CM - Pin Description

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Modified by Admin on Sep 13, 2017

The following pin description is for the WB_I2CM when used on the schematic. In an OpenBus System, although the same signals are present, the abstract nature of the system hides the pin-level Wishbone interfaces. The external interface signals will be made available as sheet entries, associated with the parent sheet symbol used to reference the underlying OpenBus System.

Table 1. WB_I2CM pin description.

Name	Type	Polarity / Bus size	Description
Control Signals
CLK_I	I	Rise	Wishbone system clock
RST_I	I	High	Wishbone system reset
Host Processor Interface Signals
STB_I	I	High	Strobe signal. When asserted, indicates the start of a valid Wishbone data transfer cycle
CYC_I	I	High	Cycle signal. When asserted, indicates the start of a valid Wishbone cycle
ACK_O	O	High	Standard Wishbone device acknowledgement signal. When this signal goes high, the Controller (Wishbone Slave) has finished execution of the requested action and the current bus cycle is terminated
ADR_I	I	3	Address bus, used to select an internal register of the device for writing to/reading from
DAT_O	O	8	Data to be sent to the host processor (valid when INT_O is asserted).
DAT_I	I	8	Data received from the host processor
WE_I	I	Level	Write enable signal. Used to indicate whether the current local bus cycle is a Read or Write cycle: 0 = Read 1 = Write
INT_O	O	High	Interrupt Signal. This line is taken High if the {{ien}} bit in the Control register is set (CONTROL.1) and the {{intreq}} bit in the Status register (STATUS.0) becomes set. The latter is set by the Controller whenever it completes its current operation.
I2C Bus Interface Signals
SDATA_EN	O	High	Output enable signal for the I2C data bidirectional buffer.
SDATAO	O	-	Serial data output.
SDATAI	I	-	Serial data input.
SCLK_EN	O	High	Output enable signal for the I2C clock bidirectional buffer.
SCLKO	O	-	Serial clock output.
SCLKI	I	-	Serial clock input.

To simplify using the bidirectional SDATA and SCLK buses, the schematic symbol includes a bus pin for each direction, allowing them to be wired independently.