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Chapter 2

PicoBlaze Interface Signals

The top-level interface signals to the PicoBlaze™ microcontroller appear in Figure 2-1and are described in Table 2-1. Figure 7-1provides additional detail on the internal structure of the PicoBlaze controller.

PicoBlaze Microcontroller

 

IN_PORT[7:0]

OUT_PORT[7:0]

 

 

 

 

INTERRUPT

PORT_ID[7:0]

 

 

 

 

RESET

READ_STROBE

 

 

 

 

 

WRITE_STROBE

 

 

 

 

 

CLK

INTERRUPT_ACK

 

 

 

 

 

 

 

 

 

UG129_c2_01_052004

 

 

Figure 2-1:PicoBlaze Interface Connections

Table 2-1:PicoBlaze Interface Signal Descriptions

 

 

 

Signal

Direction

Description

 

 

 

IN_PORT[7:0]

Input

Input Data Port: Present valid input data on this port during an INPUT

 

 

instruction. The data is captured on the rising edge of CLK.

 

 

 

INTERRUPT

Input

Interrupt Input: If the INTERRUPT_ENABLE flag is set by the application

 

 

code, generate an INTERRUPT Event by asserting this input High for at least

 

 

two CLK cycles. If the INTERRUPT_ENABLE flag is cleared, this input is

 

 

ignored.

 

 

 

RESET

Input

Reset Input: To reset the PicoBlaze microcontroller and to generate a RESET

 

 

Event, assert this input High for at least one CLK cycle. A Reset Event is

 

 

automatically generated immediately following FPGA configuration.

 

 

 

CLK

Input

Clock Input: The frequency may range from DC to the maximum operating

 

 

frequency reported by the Xilinx ISE® development software. All PicoBlaze

 

 

synchronous elements are clocked from the rising clock edge. There are no

 

 

clock duty-cycle requirements beyond the minimum pulse width

 

 

requirements of the FPGA.

 

 

 

OUT_PORT[7:0]

Output

Output Data Port: Output data appears on this port for two CLK cycles during

 

 

an OUTPUT instruction. Capture output data within the FPGA at the rising

 

 

CLK edge when WRITE_STROBE is High.

 

 

 

PicoBlaze 8-bit Embedded Microcontroller

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UG129 (v1.1.2) June 24, 2008

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Xilinx UG129 manual PicoBlaze Interface Signals, PicoBlaze Interface Signal Descriptions, Signal Direction Description