NVIC interrupts on two ports with same pin number

[jean_prieur]

Posted on September 19, 2013 at 17:37

Hello everybody,

Is it possible to link same pin number of different GPIO ports on the same EXTI line ? For example, create an interrupt on line_0 for the GPIO pin A0 and the pin B0. It seems impossible to achieve with the ST librairies - but I don't understand why it's impossible regarding to the internal schematic of the STM32F4... I really want to use more than 16 GPIO with interrupts. Is there a software way to perform this interruption ?Thanks a lot !

[Tesla DeLorean]

Posted on September 19, 2013 at 18:33

NO, it uses an N-to-1 mux, only one bank's pin reaches the signal conditioning.

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[Tesla DeLorean]

Posted on September 19, 2013 at 18:37

[jean_prieur]

Posted on September 19, 2013 at 18:56

Thanks Clive, I just wanted to sure.

[Tesla DeLorean]

Posted on September 19, 2013 at 19:11

Generally you'd use an external priority decoder to decimate the number of pins required on the CPU.

Alternatively you could use TIMx_CHx pins in input capture mode, or poll slow GPIO sources. I'd recommend a print out of the Data Sheet with pin designations, and a high-lighter pen. Assign the TIM pins first, then the EXTI. Draw a pin vs bank matrix if that helps.

[John F.]

Posted on September 20, 2013 at 09:09

For example. 74HC147

10-to-4 Line Priority Encoder

or 74HC148

8-Line To 3-Line Priority Encoder

. Also CD4532 from the old CMOS 4000 series. Also note on the STM32F4 family (STM32F405/407xx and STM32F415/417xx) this erratum - Configuration of PH10 and PI10 as external interrupts is erroneous Description PH10 or PI10 is selected as the source for the EXTI10 external interrupt by setting bits EXTI10[3:0] of SYSCFG_EXTICR3 register to 0x0111 or 0x1000, respectively. However, this erroneous operation enables PH2 and PI2 as external interrupt inputs. As a result, it is not possible to use PH10/PI10 as interrupt sources if PH2/PI2 are not selected as the interrupt source, as well. This means that bits EXTI10[3:0] of SYSCFG_EXTICR3 register and bits EXTI2[3:0] of SYSCFG_EXTICR1 should be programmed to the same value: • 0x0111 to select PH10/PH2 • 0x1000 to select PI10/PI2 Workaround None.

[sam]

Posted on March 31, 2014 at 05:01wish it was ORed...

[John F.]

Posted on March 31, 2014 at 09:25

Then just use an external single OR gate such as the SN74LVC1G32DBVR (Texas version of 74LVC1G32 single OR gate). Alternatively, if you need a '0' OR (output low if either input low) the SN74LVC1G08DBVR AND gate will do.