AT89LP6440 datasheet(155/194 Pages) ATMEL

155 / 194 page

155

3706A–MICRO–9/09

AT89LP6440 - Preliminary

24. On-Chip Debug System

The AT89LP6440 On-Chip Debug (OCD) System uses a two-wire serial interface to control pro-

gram flow; read, modify, and write the system state; and program the nonvolatile memory. The

OCD System has the following features:

• Complete program flow control

•Read-Modify-Write access to all internal SFRs and data memories

•Four hardware program address breakpoints, plus four program/data address breakpoints

• Unlimited program software breakpoints using BREAK instruction

•Break on change in program memory flow

•Break on stack overflow/underflow

•Break on Watchdog overflow

•Break on reset

• Non-intrusive operation

•Programming of nonvolatile memory

24.1

Physical Interface

The On-Chip Debug System uses a two-wire synchronous serial interface to establish communi-

cation between the target device and the controlling emulator system. The OCD interface is

enabled by clearing the OCD Enable Fuse. The OCD device connections are shown in Figure

24-1. When OCD is enabled, the RST port pin is configured as an input for the Debug Clock

(DCL). Either the XTAL1, XTAL2 or P4.3 pin is configured as a bi-directional data line for the

Debug Data (DDA) depending on the clock source selected. If the Internal RC Oscillator is

selected, XTAL1 is configured as DDA (A).If the External Clock is selected, XTAL2 is configured

as DDA (B). If the Crystal Oscillator is selected, P4.3 is configured as DDA (C).

When designing a system where On-Chip Debug will be used, the following observations must

be considered for correct operation:

TH0

8CH

Table 11-1 on page 50

TH1

8DH

Table 11-1 on page 50

TH2

CDH

Section 12.1 on page 60

TL0

8AH

Table 11-1 on page 50

TL1

8BH

Table 11-1 on page 50

TL2

CCH

Section 12.1 on page 60

TMOD

89H

Table 11-3 on page 54

TWAR

ACH

Table 18-3 on page 111

TWBR

AEH

Table 18-5 on page 112

TWCR

AAH

Table 18-1 on page 111

TWDR

ADH

Table 18-4 on page 112

TWSR

ABH

Table 18-2 on page 111

WDTCON

A7H

Table 21-2 on page 142

WDTRST

A6H

Table 21-3 on page 142

Table 23-1.

Special Function Register Cross Reference

AT89LP6440 Datasheet(PDF) 155 Page - ATMEL Corporation

AT89LP6440 Datasheet(HTML) 155 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL