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June 2008 Rev 2 1/4
AN593
APPLICATION NOTE
ST62 in-circuit programming
In-circuit programming feature
The in-circuit programming process allows pro-
gramming or reading of the non volatile memory of
an ST62 device already fixed on the application
board. This feature applies both to the EPROM
memory containing the user ROM (Executable
code and constants) and to the EEPROM content
(Non volatile data). The capability to program
memory locations initially unprogrammed and ac
-
cess the user ROM content allows a wide range of
applications enhancement: Storage of informa
-
tions after a maintenance operation on field, fol-
low-up of the software revision on field, update of
non volatile data space, In addition, this in-circuit
programming process limits the handling on com
-
plex packages like PQFP since the handling cy-
cles for the programming is suppressed and only
the handling for the soldering on PCB is needed.
This note provides information on the steps re-
quired in order to perform in-circuit programming
of ST62Exxx EPROM or OTP devices for both on-
chip EPROM and EEPROM.
In-circuit programming procedure
During the in-circuit programming progress, the
application board is used as remote socket for the
programming tool and the programming process
and software remains unchanged. The connection
of the application board to/from the programming
tool is made through a 16 pin cable plugged into a
16 pin connector (8x2 header HE10). That 16 pin
connector has to be provided by the designer on
the application board.
The connections between the 16 pins connector
and the ST62 are summarized below:
Note: The connection to the pin3 of the connector
is not necessary if a high voltage level is guaran
-
teed by the application design (See Application
design guidelines)
The VDD connection is optional depending wheth-
er or not the application supply can be disconnect-
ed. If the application supply is disconnected, it is
possible to supply the application board through
the pins 14 and 16 of the connector as long as the
total load current does not exceed 100mA and the
capacitive load is lower than 50F. In the opposite,
if the application board keeps its own supply, the
supply value must be set at 5V in order to be com
-
patible with the signal levels to/from the program-
ming tool.
Figure 1. 16-pin PCB Socket Connection
ST621x/2x ST624x
ST626x/9x
PA6
PA5
OSCin
PA7
RESETRESET
PB7
OSCin
PB5
PB6
Not used
RESET
PB2
OSCin
PB0
PB3
Connect to:
1
3
5
7
9
11
13
NC
14
12
10
8
6
4
2
16
HE10
TOP VIEW
Connect to ALL
VR01856
NC
NC
NC
15
Serial in
Serial out
V
SS
of
Application Board
V
DD
Optional
V
PP
/ TMV
PP
/ TM
V
PP
/ TM
PC6
PC5
PC7
RESET
ST628x
OSCin
Not used
Not used
Not used
V
PP
/ TM
