Posted on May 17, 2011 at 12:53I am quite new to the microcontroller field and ran into a problem modding the code from the GPIO IOtoggle example given to you in the um0427 download from STMicro. I am using IAR Embeded IDE and am trying to output toggled bits on the Daughter board extension connector CN10.
I am able to toggle the LED bits fine with the original code, but when i try to change ports(to Port B) and add additional pins (3, 4, 5) I am not able to toggle outputs on pins 3 and 4 (CN10.PB3.PB4). The outputs on these pins remain pulled up to 3.3Volts even when i do a GPIO_ResetBits(all_pin).
I see toggling of the bits on the pins I want (5, 6, 7, 8 and 9), however, the output voltage of the pin toggled is only 1.25V. So I do not know why I am seeing this output when toggled high and it is a problem because I need a Vh logic value of at least 2.4V for my application. Below is the some modded code, where GPIO_lo1 is defined as GPIOB. One thought is that I have not enabled the clocks for gpio3 and gpio4 but have not found anything to explicitly enable those clocks (ie. existing code for the other clocks gpio5-gpio9). Any insight on this matter would be greatly appreciated, thank you!
~G
//enable clock
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIO_lo1, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3 | GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIO_lo1, &GPIO_InitStructure);
while (1)
{
GPIO_ResetBits(GPIO_lo1, GPIO_Pin_All);
GPIO_SetBits(GPIO_lo1, GPIO_Pin_7);
}
