STMicroelectronics STM8A Manuals

The STM8A/128-EVAL evaluation board is designed as a complete development platform for the STM8 core-based STM8AXX microcontroller with CAN2.0A/B compliant interface, I2C, SPI, two UART channels with smartcard, IrDA and LIN support, internal 2 Kbyte data Flash and 128 Kbyte Flash program memory, SWIM debugging support.

The purpose of this application note is to explain how to keep real-time information on a STM8S or STM8A device maintained in low power mode. Only simple solutions which do not require any additional hardware are described in this application note. They are suitable for applications which do not need a very accurate real- time measurement. To benefit fully from the information in this application note, the user should be familiar with the STM8S and STM8A microcontroller architecture and with the basics of C language. For further information on the STM8S and STM8A family features, pinout and electrical characteristics, please refer to the STM8S and STM8A datasheets. An STM8S and STM8A firmware package is delivered with this application note. It contains the complete C source code of an example described in this application note, so that the user can compile, link or modify it as necessary. This document and its associated firmware package, are written to accompany the STM8S and STM8A firmware library. It includes many examples describing how to use the STM8S and STM8A timers, the clock system, the beeper and the auto-wakeup unit mentioned in this application note.

This application note describes how to emulate the UART behavior and functionality using routines in STM8S microcontrollers. The UART peripheral is emulated on hardware that has the capture & compare interrupt capability. Such emulation is useful in applications that require more than one UART, or when the dedicated serial communication hardware peripherals are being used in another way. This software solution is suitable for standard full-duplex speeds of up to 57 600 Bd for the core running at 24 MHz or, of up to 19200 Bd for the core running at 16 MHz. Its main feature is that it runs in the background with a time reserve, so that the main process stream can continue and control the rest of the application processes. The higher communication speeds can be achieved when polling and controlling I/O pins in the main stream, but, as a result, the control of all other application processes is sidetracked while receiving or sending a message and the full-duplex capability might even be lost. Standard data frame formats are supported, as well as options like parity, ninth data bit and double stop bit. Double data registers, noise detection logic, frame generation and overflow logic are implemented with minimum MCU hardware usage. A firmware package is delivered with this document. It contains the complete C source code so that the user can compile.

This application note describes the easy programmer which is a low cost solution allowing the content of the STM8A Flash program memory to be updated when the chip is already soldered on the application board.

This application note describes a technique to emulate the universal asynchronous receiver transmitter (UART) hardware peripheral, through the microcontroller medium end timer (TIMER3), without the use of additional hardware. TIMER3 was chosen for this purpose because its capture and compare features can be easily used to receive and transmit data in a non return to zero (NRZ) serial format. This timer also provides a necessary time reference to establish when to send and read each outgoing and incoming data frame bit. In addition, TIMER3 was chosen because it has all the necessary features to build a software UART. Features include two timer channels, one for transmission (TIMER3_CC2) and one for reception (TIMER3_CC1). The input capture feature of channel one allows detection of an incoming data frame start bit, whereas its compare feature indicates when the bits have to be read. The output compare feature of channel two allows transmission of a data frame. The algorithm described in this document is an example which can be further customized and improved. It is explained in Section 7: The UART emulator software algorithm on page 14, together with information on how to configure and use a UART emulator. The algorithm handles several UART hardware features via software such as, selection of the operating mode, noise and frame error detection, programmable data word length and configurable stop