Real Time Timer Controller Interface Peripheral

RTTC (AT91S_RTTC) 0xFFFFFD20 (AT91C_BASE_RTTC)

RTTC Software API (AT91S_RTTC)

Offset Field Description
0x0RTTC_RTMR (SYSC_RTMR)Real-time Mode Register
0x4RTTC_RTAR (SYSC_RTAR)Real-time Alarm Register
0x8RTTC_RTVR (SYSC_RTVR)Real-time Value Register
0xCRTTC_RTSR (SYSC_RTSR)Real-time Status Register

RTTC Register Description

RTTC: AT91_REG SYSC_RTMR - Real-time Mode Register

Offset Name Description
15..0SYSC_RTPRES
AT91C_SYSC_RTPRES
Real-time Timer Prescaler Value
Defines the number of SLCK periods required to increment the Real-time Timer. The maximum period is obtained by programming RTPRES to 0x0 corresponding to 65536 Slow Clock cycles.
16SYSC_ALMIEN
AT91C_SYSC_ALMIEN
Alarm Interrupt Enable
0 = The bit ALMS in SYSC_RTSR has no effect on SCIRQ.
1 = The bit ALMS in SYSC_RTSR asserts SCIRQ.
17SYSC_RTTINCIEN
AT91C_SYSC_RTTINCIEN
Real Time Timer Increment Interrupt Enable
0 = The bit RTTINC in SYSC_RTSR has no effect on SCIRQ.
1 = The bit RTTINC in SYSC_RTSR asserts SCIRQ.
18SYSC_RTTRST
AT91C_SYSC_RTTRST
Real Time Timer Restart
0 = No effect.
1 = Reloads and restarts the clock divider with the new programmed value. This also resets the 32-bit counter.

RTTC: AT91_REG SYSC_RTAR - Real-time Alarm Register

Offset Name Description
31..0SYSC_ALMV
AT91C_SYSC_ALMV
Alarm Value
Defines the Alarm value compared with the Real-time Timer.

RTTC: AT91_REG SYSC_RTVR - Real-time Value Register

Offset Name Description
31..0SYSC_CRTV
AT91C_SYSC_CRTV
Current Real-time Value
Returns the current value of the Real-time Timer.

RTTC: AT91_REG SYSC_RTSR - Real-time Status Register

Offset Name Description
0SYSC_ALMS
AT91C_SYSC_ALMS
Real-time Alarm Status
0 = The Real-time Alarm has not occured since the last read of SYSC_RTSR.
1 = The Real-time Alarm occured since the last read of SYSC_RTSR.
1SYSC_RTTINC
AT91C_SYSC_RTTINC
Real-time Timer Increment
0 = The Real-time Timer has not been incremented since the last read of SYSC_RTSR.
1 = The Real-time Timer has been incremented since the last read of SYSC_RTSR.