Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Keil/AT32F413xx_v2/DMA1/DMA_SRC_SEL0#0x0
DMA channel source assignment register
CH1 SRC select
CH2 SRC select
CH3 SRC select
CH4 SRC select
https://github.com/cmsis-svd/cmsis-svd-data