ST STM32F412 Reference Manual page 722

Fast-mode Plus Inter-integrated circuit (FMPI2C) interface RM0402
Table 131. FMPI2C register map and reset values (continued)
Register
Offset
name
FMPI2C_TXDR TXDATA[7:0]
0x28
Reset value 0 0 0 0 0 0 0 0
Refer to Section 2.2 on page 49 for the register boundary addresses.
722/1163 RM0402 Rev 6