Hi, I try to configure the ADC of a STM32F407 to work in triple injected simultaneous mode, but only ADC1 works. How do I have to configure the ADC's that they work simultaneous?

[ATasc]

As stated in the Reference manual. I configure the master ADC1 to get the trigger from the TIM2 TRGO and this ADC1 is working when started. ADC2 and ADC3 start only when I configure JEXTEN (=0x01) and JEXTSEL (=0x03) in CR2 of the according ADC. I don't know howw to use the common trigger as stated in the reference manual:

"13.9.1 Injected simultaneous mode

This mode converts an injected group of channels. The external trigger source comes from

the injected group multiplexer of ADC1 (selected by the JEXTSEL[3:0] bits in the ADC1_CR2

register). A simultaneous trigger is provided to ADC2 and ADC3." from DocID018909 Rev 15

Thanks for your help in advance.