62.4.4.1.1 TDES_MR.LOD = 0

The DATRDY flag is cleared when at least one TDES_ODATARx is read. See the figure below.

Figure 62-2. Manual and Auto Modes with LOD = 0

If the user does not want to read TDES_ODATARx between each encryption/decryption, the DATRDY flag will not be cleared. If the DATRDY flag is not cleared, the user will not be informed of the end of the encryptions/decryptions that follow.