AN2792

Software and hardware requirements

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5

Software and hardware requirements

5.1

Batch file

The STxx boot loader tester tool, used to load files into the application board, manages .s19

files in a standard format. There are 16 bytes for single string and increase addresses

options (option -m16 and -s respectively). To produce a .s19 file with both these options, the

following check option must be added:

Es.

"%COS_PATH%\chex" -m16 -s ".\%PRJ_PATH%\%PRJ_NAME%.st7" >

".\PRJ_PATH\%PRJ_NAME%.s19"

COS_PATH is the COSMIC compiler path

PRJ_NAME is the name of the project

5.2

Application software

To program the application board of the STM8A, the device must be in boot mode (see

Section 4: Transfering the .s19 file to the STM8A application board on page 8). If the device

is not in boot mode, the easy programmer must write two option bytes (487Eh and 487Fh).

This is done by the easy programmer sending a pulse on the PH4 pin which is connected to

the external interrupt pin of the application board (PORTx/pin). This external interrupt forces

the application code to execute the interrupt routine that writes the option bytes and resets

the device (the option bytes are updated with the new values only after reset). The interrupt

routine code is as follows:

@interrupt void EXTI_PORTx_IRQHandler (void)

{

volatile u8 opt

@0x487E;

volatile u8 nopt @0x487F;

if ( GPIOx.IDR & 0xPin )

{

/* Enable write to EEProm Data */

FLASH.DUNPR = 0xAE;

FLASH.DUNPR = 0x56;

/* Enable write to option byte */

FLASH.CR2 |= 0x80;

FLASH.NCR2 &= 0x7F;

/* Write option byte */

opt = 0x55;

nopt = 0xAA;

/* Reset micro with LSWDG */

IWDG.KR = 0xCC;

IWDG.KR = 0x55;

}

return;

}

‘PORTx’ and ‘pin’ indicate any pin of PORTx with external interrupts. Pins can be chosen

from any available I/0 pin of the application board.