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

RESET

RESET

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

Application Board

V

V

V

V

PC6

PC5

PC7

RESET

ST628x

OSCin

Not used

Not used

Not used

V