WB_LCDCTRL - Pin Description
Frozen Content
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 |
| 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 |
| 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 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 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 |