AN3259

Prerequisites

Doc ID 17835 Rev 1

5/25

1

Prerequisites

The material required to run the STM8S-DISCOVERY terminal demonstration application is

the following:

●

A terminal window running on a PC: the terminal emulator software can be Windows

Hyperterminal (see Appendix B), TeraTerm Pro, or any terminal software.

●

An RS232 null-modem cable (transmit and receive line crosslinked).

2

Configuring the STM8S-DISCOVERY

Prior to running the application, the STM8S-DISCOVERY must be configured to enable the

beeper output. The beeper output is an STM8S105C6T6 alternate function. It is enabled by

setting the alternate function remap option bit AFR7 in OPT2 option byte to ‘1’.

For details on alternate function remapping and on option bytes, refer to user manual

“Developing and debugging your STM8S-DISCOVERY application code” (UM0834), and to

the STM8S105xx datasheet, respectively.

3

Application description

3.1

Hardware required

This application uses STM8S-DISCOVERY on-board LED (LD1) together with its associated

resistor (R1).

The external passive components required by the application are listed inTable 1.

The application also makes use of a 5 V powered ST232B RS232 driver/receiver (see

Table 2). This extra component is essential since the COM port of the PC operates from a

nominal 12 V power supply. This is not compatible with the STM8S UART input/outputs

operating at 5 V. This component is available in an SO16 package which fits the STM8S-

DISCOVERY footprint. For more information on the ST232B refer to the ST232B datasheet.

Table 1.

List of passive components

Component description

Value

B1 buzzer

-

C1,C2,C3,C4,C5 capacitors

100 nF

DB9 connector

-