DocID018532 Rev 3

5/13

PM0083

Software interface

2

Software interface

2.1

Command overview

The following programming mode serial commands are used in the procedures described in

this section.

2.2

Write a byte to the STM8T143

Prerequisite: POUT = HIGH and CX must be configured as input on the programming tool

before calling the write procedure.

Table 2. List of commands

Command

Description

0x30

Read an indirect addressed byte from RAM.

0x40

Write an indirect addressed byte to RAM (writes data to a RAM address of

the device during the next two serial command communication cycles.)

0x60

Program the specified option byte.

0xF0

Request acknowledge.

Table 3. Write procedure

Step

Action

Description

1.

Wait for CX = HIGH

Wait for device to pull CX high to indicate that it is ready to receive.

2.

POUT = LOW and wait

50 µs

Pull POUT low as part of handshaking protocol.

3.

POUT = HIGH

Pull POUT high before clocking out the data to the device.

4.

Configure CX as output

and wait 50 µs

Programming tool takes control of data on CX.

5.

Clock out data to device

(8 bits)

Clock out 8 data bits on CX at a clock frequency of 8.8 kHz on

POUT. (Clock on POUT ten times faster than it was during

programming mode entry.). Data on CX must be set up while clock

on POUT is low. Most significant bit transmitted first. End sequence

with POUT high.

6.

POUT = LOW

Pull POUT low after 8th bit.

7.

Configure CX as input

and wait 50 µs

Programming tool releases control of data on CX and waits 50 µs.

8.

POUT = HIGH

Pull POUT high to end the writing sequence.