AT89C5131A Starter Kit Hardware User Guide
3-9
Rev. 4245A–USB–11/04
Section 3
Device Programming
3.1
In-System
Programming
The user memory of the AT89C5131A part can be programmed using the ISP mode of
the device. In order to enter in ISP mode, first select the high pin count mode (PSEN) or
the low pin count mode (P1.0) using the ISP switch (SW2).
To enter in ISP mode, press both the RESET (SW3) and ISP (SW4) buttons simulta-
neously. First release the RESET button and then the ISP button. The device enters in
ISP mode.
ISP can then be performed using the USB bus (or with the peripheral corresponding
with the bootloader version). The user may need to re-enumerate the USB bus using the
USB UNLOAD button (SW1) if the USB cable is already connected.
3.2
Using a
Programmer
The AT89C5131A microcontroller can also be programmed using a programmer with
the J3 connector. Connect all required signals between the programmer and the J3 con-
nector and remove the J7 jumper to disconnect the EA circuitry. No clock should be
enabled on the board, except the clock coming from the J3 connector.
Figure 3-1. J3 Connector Schematic
1
VCC
2
VSS
3
XTAL1
4
VSS
5
NC
6
RST
7
P3.2 (Test0)
8
VSS
9
P3.4 (Test1)
10
VSS
J3
