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AT89ISP Programmer Cable
1. Introduction
This application note describes the Atmel AT89ISP cable interface. This in-system
programmer cable communicates serially with Atmel's AT89S/AT89LP microcontrol-
lers and reprograms them in the circuit without removal. For surface-mounted devices,
eliminating this step greatly reduces the possibility of damages caused by inser-
tion/removal of delicate leads, and allows for design changes and software/parameter
updates in the field.
2. AT89ISP Software
The AT89ISP software is the primary means for performing in-system program-
ming (ISP) of Atmel AT89S/AT89LP devices. It provides an intuitive interface for in-
system programming that can be run from a personal computer. The software will run
under the Windows
®
9x/ME/2000/XP, Windows NT
®
operating systems. The software
has a comprehensive set of features that allows a user to view, program, and erase
data from an Atmel AT89S/AT89LP device. A detailed Adobe
®
Acrobat
®
document
describing the features/functions of the software accompanies it.
3. AT89ISP Cable
In order to use the AT89ISP software, the user will need to have an Atmel AT89ISP
cable. This cable can be purchased directly from Atmel or authorized Atmel represen-
tatives. The ISP cable's pins need to be connected to an AT89S/AT89LP device in the
manner shown in Figure 4-1 on page 2. The 25-pin male connector plugs into the par-
allel port of the user’s personal computer. The 10-pin female IDC header plugs into a
10-pin male header in the user’s target board. A polarized 10-pin receptacle male
header is highly recommended to avoid an erroneous connector mating. The pinout
shown below represents the target 10-pin male header connector in the user's board
as viewed from the top. Please note that connection of the SS
pin (P1.4) is
required for all the AT89LP (single-cycle core) derivatives, but not for the AT89S
derivatives.
Figure 3-1. AT89ISP Cable 10-pin Male Header Pinout
Note: NC = Not Connected.
2
4
6
8
10
1
3
5
7
9
(SCK) P1.7
(MISO) P1.6
RST
NC
(MOSI) P1.5
GND
VCC
NC
P1.4 (SS)
GND
AT89ISP
Programmer
Cable
Application
Note
3310D–MICRO–6/05
