Posted on May 17, 2011 at 13:35Greetings to you all!
Recently Im trying my best to have my I2C ICs functioning.
First of all configuration:
* STM32F107
* Keil uVision v4.00 + compiler
* I2C temperature IC with 10k pull-up resistor on SCL and SDA,
software bit banging I2C protocol - I dont want to use built-in one, dont ask why.
I couldnt manage to make it working so I started to debug.
I was trying to read the state of output pin (SDA, output open-drain), which configuration is:
Code:
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_DeInit(GPIOB);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
also to make it sure that my code is working Iv configured another pin as input floating which is connected to a microswitch and a pull-up resistor:
Code:
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOE, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11 | GPIO_Pin_12;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOE, &GPIO_InitStructure);
read procedure:
Code:
while (1)
{
if(GPIO_ReadOutputDataBit(I2C, SDA) == 1)
{
GPIO_ResetBits(LED, LED1);
}
else
{
GPIO_SetBits(LED, LED1);
}
if(GPIO_ReadInputDataBit(GPIOE, GPIO_Pin_10) == 1)
GPIO_ResetBits(LED, LED2);
else
GPIO_SetBits(LED, LED2);
}
LED, LED1, LED2, I2C, SDA are #define of pins and ports.
GPIO_Pin_10 is a button.
Second 'if' turn on/off a LED whenever a button is pushed.
Unfortunately I have completely no idea why when Im reading my SDA pin it is always '1', even when I short this pin to the ground :(
Can anybody help me with this out?
Thanks! and sorry for my bad english.
Cheers!
