IO MUX remap register
| SPI1_MUX0 | SPI1 muxing bit0 |
| I2C1_MUX | I2C1 muxing |
| USART1_MUX | USART1 muxing |
| USART3_MUX | USART3 muxing |
| TMR1_MUX | TMR1 muxing |
| TMR2_MUX | TMR2 muxing |
| TMR3_MUX | TMR3 muxing |
| CAN_MUX | CAN1 muxing |
| PD01_MUX | PD0/PD1 muxing on OSCIN/OSCOUT |
| TMR5CH4_MUX | TMR5 channel4 internal muxing |
| ADC1_ETP_MUX | ADC1 external trigger preempted conversion muxing |
| ADC1_ETO_MUX | ADC1 external trigger ordinary conversion muxing |
| SWJTAG_MUX | SWD JTAG muxing |
| SPI1_MUX1 | SPI1 muxing bit1 |