WB_LCDCTRL - Pin Description

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Modified by Admin on Nov 6, 2013

The following pin description is for the WB_LCDCTRL 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_LCDCTRL Pin description.

Name	Type	Polarity / Bus size	Description
Control Signals
CLK_I	I	Rise	External (system) clock
RST_I	I	High	External (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	Level	Address bus. For the WB_LCDCTRL, this input is internally connected directly to the LCD_RS output, providing the data/instruction select signal to the LCD panel: 0 = Instruction 1 = Data
DAT_O	O	8	Data to be sent to host processor
DAT_I	I	8	Data received from 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
LCD Panel Interface Signals
LCD_E	O	High	Enable signal to the LCD panel (corresponds to E pin on most LCD panels).
LCD_RW	O	Level	Read/Write select signal to the LCD panel (corresponds to the RW pin on most LCD panels). 0 = Write 1 = Read Note: This output adheres to the following logical expression: `LCD_RW = STB_I AND CYC_I AND (NOT WE_I)`
LCD_RS	O	Level	Data/Instruction select signal to the LCD panel (corresponds to the RS pin on most LCD panels). 0 = Instruction 1 = Data Note: This signal directly follows the state of the ADR_I input
LCD_DATA	O	8	Bidirectional data bus to/from the LCD panel (corresponds to the DB bus on most LCD panels). When writing to the LCD, data is channeled from the DAT_I input to this bus. When reading from the LCD, data is channeled from this bus to the DAT_O line