peripheral mode configuration register
| I2C1FMP | I2C1 Fm+ |
| I2C2FMP | I2C2 Fm+ |
| I2C3FMP | I2C3 Fm+ |
| I2C4FMP | I2C4 Fm+ |
| PB6FMP | PB(6) Fm+ |
| PB7FMP | PB(7) Fast Mode Plus |
| PB8FMP | PB(8) Fast Mode Plus |
| PB9FMP | PB(9) Fm+ |
| BOOSTE | Booster Enable |
| BOOSTVDDSEL | Analog switch supply voltage selection |
| EPIS | Ethernet PHY Interface Selection |
| PA0SO | PA0 Switch Open |
| PA1SO | PA1 Switch Open |
| PC2SO | PC2 Switch Open |
| PC3SO | PC3 Switch Open |