STMicroelectronics STM8 Manual page 49

delay_ms(90);
}
while (TRUE);
}
void clock_setup(void)
{
CLK_DeInit();
CLK_HSECmd(DISABLE);
CLK_LSICmd(DISABLE);
CLK_HSICmd(ENABLE);
while(CLK_GetFlagStatus(CLK_FLAG_HSIRDY) == FALSE);
CLK_ClockSwitchCmd(ENABLE);
CLK_HSIPrescalerConfig(CLK_PRESCALER_HSIDIV8);
CLK_SYSCLKConfig(CLK_PRESCALER_CPUDIV1);
CLK_ClockSwitchConfig(CLK_SWITCHMODE_AUTO, CLK_SOURCE_HSI,
DISABLE, CLK_CURRENTCLOCKSTATE_ENABLE);
CLK_PeripheralClockConfig(CLK_PERIPHERAL_SPI, DISABLE);
CLK_PeripheralClockConfig(CLK_PERIPHERAL_I2C, DISABLE);
CLK_PeripheralClockConfig(CLK_PERIPHERAL_ADC, DISABLE);
CLK_PeripheralClockConfig(CLK_PERIPHERAL_AWU, DISABLE);
CLK_PeripheralClockConfig(CLK_PERIPHERAL_UART1, DISABLE);
CLK_PeripheralClockConfig(CLK_PERIPHERAL_TIMER1, DISABLE);
CLK_PeripheralClockConfig(CLK_PERIPHERAL_TIMER2, DISABLE);
CLK_PeripheralClockConfig(CLK_PERIPHERAL_TIMER4, DISABLE);
}
void GPIO_setup(void)
{
GPIO_DeInit(LCD_PORT);
}
Explanation
There's little to explain this code as it involves GPIOs only. The codes for the LCD are coded using all
available info on its datasheet, just initialization and working principle. One thing to note, however, is
the CPU clock speed. If the CPU clock is too fast, LCDs may not work. This is because most LCDs have
a maximum working frequency of 250kHz. It is best to keep this frequency below 200kHz.
CLK_HSIPrescalerConfig(CLK_PRESCALER_HSIDIV8);
CLK_SYSCLKConfig(CLK_PRESCALER_CPUDIV1);