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OnCE™ Module

12.4.4.9 Breakpoint Enable (BE[1:0])—Bits 1–0

The breakpoint enable (BE[1:0]) control bits enable or disable the breakpoint logic and select the type of memory operations (read, write, or access) upon which the breakpoint logic operates. Access means either a read or write can be taking place. These bits are cleared on hardware reset. Table 12-12 describes the bit functions.

 

Table 12-12. BE[1:0] Bit Definition

 

 

 

BE[1:0]

 

Selection

 

 

 

 

 

 

00

 

Breakpoint disabled

 

 

 

01

 

Breakpoint enabled on memory write

 

 

 

10

 

Breakpoint enabled on memory read

 

 

 

11

 

Breakpoint enabled on memory access

 

 

 

The BE[1:0] bits work in conjunction with the BS[1:0] bits to determine how the address breakpoint hardware is set up. The decoding scheme for BS[1:0] and BE[1:0] is shown in Table 12-11. Breakpoints should remain disabled until after the OBAR is loaded. See Section 12.5.5, “OnCE Breakpoint and Trace Section,” and Section 12.9.2, “Entering Debug Mode,” for a more complete description of tracing and breakpoints. Breakpoints can be disabled or enabled for one memory space.

12.4.5 OnCE Breakpoint 2 Control Register (OBCTL2)

The OnCE breakpoint 2 control register (OBCTL2) is a 3-bit register used to program breakpoint 2. It can be read or written by the OnCE unit. It is used to set up the second breakpoint for breakpoint operation. This register is accessed as the lowest 3 bits of a 16-bit word. The upper bits are reserved and should be written with zero to ensure future compatibility.

12.4.5.1 Reserved OBCTL2 Register Bits

Bits 15–3 are reserved and are read as zero during read operations. These bits should be written with zero to ensure future compatibility.

12.4.5.2 Enable (EN)—Bit 2

The enable (EN) bit is used to enable the second breakpoint unit. When EN is set, the second breakpoint unit is enabled. When EN is cleared, the second breakpoint unit is disabled.

12.4.5.3 Invert (INV)—Bit 1

The invert (INV) bit is used to specify whether to invert the result of the comparison before sending it to the breakpoint and trace unit. When INV is set, then the second breakpoint unit inverts the result of the comparison. When INV is cleared, no inversion is performed.

12-20

DSP56824 User’s Manual

 

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