52.6.2 TZAESB Mode Register

This register can only be written if WPEN is cleared in the TZAESB Write Protection Mode Register.

Name: TZAESB_MR
Offset: 0x04
Reset: 0x00000004
Property: Read/Write

Bit 3130292827262524 
 TAMPCLR        
Access R/W 
Reset 0 
Bit 2322212019181716 
 CKEY[3:0]     
Access R/WR/WR/WR/W 
Reset 0000 
Bit 15141312111098 
  OPMOD[2:0]     
Access R/WR/WR/W 
Reset 000 
Bit 76543210 
 PROCDLY[3:0]     
Access R/WR/WR/WR/W 
Reset 0000 

Bit 31 – TAMPCLR Tamper Clear Enable

ValueDescription
0

A tamper detection event has no effect on the TZAESB_KEYWRx key.

1

A tamper detection event immediately clears the TZAESB_KEYWRx key.

Bits 23:20 – CKEY[3:0] Key

ValueNameDescription
0xE PASSWD

Must be written with 0xE the first time that TZAESB_MR is programmed. For subsequent programming of TZAESB_MR, any value can be written, including that of 0xE.

Always reads as 0.

Bits 14:12 – OPMOD[2:0] Operating Mode

If OPMOD is set to 4, there is no compliance with the standard CTR mode of operation but the mode of operation is derived from CTR mode.

Values which are not listed in the table must be considered as “reserved”.

ValueNameDescription
0

Reserved

1

Reserved

2

Reserved

3

Reserved

4 CTR

Counter mode (16-bit internal counter)

Bits 7:4 – PROCDLY[3:0] Processing Delay

The best performance is achieved with PROCDLY equal to 0.

Processing Time = 12 × (PROCDLY + 1)

The Processing Time represents the number of clock cycles that the TZAESB needs in order to perform one encryption/decryption .