Altera Nios II Custom Manual de usuario descargar pdf (Pagina 10)

1–6 Chapter 1: Nios II Custom Instruction Overview

Custom Instruction Types

Nios II Custom Instruction User Guide January 2011 Altera Corporation

Figure 1–5 shows the multicycle custom instruction block diagram.

Multicycle custom instructions complete in either a fixed or variable number of clock

cycles. For a custom instruction that completes in a fixed number of clock cycles, you

specify the required number of clock cycles at system generation. For a custom

instruction that requires a variable number of clock cycles, you instantiate the

start

and

done

ports. These ports participate in a handshaking scheme to determine when

the custom instruction execution is complete.

Table 1–3 describes the multicycle custom instruction ports.

As indicated in Table 1–3, the

clk

clk_en

, and

reset

ports are required for multicycle

custom instructions. However, the

start

done

dataa

datab

, and

result

ports are

optional. Implement them only if the custom instruction functionality requires them.

Figure 1–5. Multicycle Custom Instruction Block Diagram

dataa[31..0]

datab[31..0]

clk

clk_en

reset

start

Multi-cycle

done

result[31..0]

Table 1–3. Multicycle Custom Instruction Ports

Port Name Direction Required Description

clk

Input Yes System clock

clk_en

Input Yes Clock enable

reset

Input Yes Synchronous reset

start

Input No Commands custom instruction logic to start execution

done

Output No

Custom instruction logic indicates to the processor that execution is

complete

dataa[31:0]

Input No Input operand to custom instruction

datab[31:0]

Input No Input operand to custom instruction

result[31:0]

Output No Result of custom instruction

1 2 ... 5 6 7 8 9 10 11 12 13 14 15 ... 49 50

Comentarios a estos manuales

Sin comentarios

Altera Nios II Custom Manual de usuario Pagina 10

Comentarios a estos manuales

Relacionado con productos y manuales para Instrumentos de medición Altera Nios II Custom