Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Data Sheet

Product codes

ATSAM4E-XPRO

SAM4E [DATASHEET]

Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14

848

Figure 36-33. Read Write Flowchart in Slave Mode

36.7.6 Register Write Protection

To prevent any single software error from corrupting TWI behavior, certain registers in the address space can be
write-protected by setting the WPEN bit in the

TWI Write Protection Mode Register

(TWI_WPMR).

If a write access to a write-protected register is detected, the WPVS flag in the

TWI Write Protection Status

(TWI_WPSR) is set and the field WPVSRC indicates the register in which the write access has been

attempted.

The WPVS bit is automatically cleared after reading the TWI_WPSR.

The following registers can be write-protected:



TWI Slave Mode Register



TWI Clock Waveform Generator Register

Set the SLAVE mode:

SADR + MSDIS + SVEN

SVACC = 1 ?

TXCOMP = 1 ?

GACC = 1 ?

Decoding of the

programming sequence

Prog seq

OK ?

Change SADR

SVREAD = 0 ?

Read Status Register

RXRDY= 0 ?

Read TWI_RHR

TXRDY= 1 ?

EOSACC = 1 ?

Write in TWI_THR

END

GENERAL CALL TREATMENT