SAM9RL64 Atmel Corporation, SAM9RL64 Datasheet - Page 124

• Manufacturer Part Number: SAM9RL64
• Manufacturer: Atmel Corporation

Specifications of SAM9RL64

• Flash (kbytes): 0 Kbytes
• Pin Count: 217
• Max. Operating Frequency: 240 MHz
• Cpu: ARM926
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 118
• Ext Interrupts: 118
• Usb Transceiver: 1
• Usb Speed: Hi-Speed
• Usb Interface: Device
• Spi: 1
• Twi (i2c): 2
• Uart: 5
• Ssc: 2
• Sd / Emmc: 1
• Graphic Lcd: Yes
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 6
• Adc Resolution (bits): 10
• Adc Speed (ksps): 220
• Resistive Touch Screen: Yes
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 64
• Self Program Memory: NO
• External Bus Interface: 1
• Dram Memory: sdram
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8/3.3
• Operating Voltage (vcc): 1.08 to 1.32
• Fpu: No
• Mpu / Mmu: No / Yes
• Timers: 3
• Output Compare Channels: 3
• Input Capture Channels: 3
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

20.4.1
20.4.2
20.4.3
20.4.4
124
AT91SAM9R64/RL64
Reference Clock
Timing
Alarm
Error Checking
The valid year range is 1900 to 2099, a two-hundred-year Gregorian calendar achieving full Y2K
compliance.
The RTC can operate in 24-hour mode or in 12-hour mode with an AM/PM indicator.
Corrections for leap years are included (all years divisible by 4 being leap years, including year
2000). This is correct up to the year 2099.
After hardware reset, the calendar is initialized to Thursday, January 1, 1998.
The reference clock is Slow Clock (SLCK).
During low power modes of the processor (idle mode), the oscillator runs and power consump-
tion is critical. The crystal selection has to take into account the current consumption for power
saving and the frequency drift due to temperature effect on the circuit for time accuracy.
The RTC is updated in real time at one-second intervals in normal mode for the counters of sec-
onds, at one-minute intervals for the counter of minutes and so on.
Due to the asynchronous operation of the RTC with respect to the rest of the chip, to be certain
that the value read in the RTC registers (century, year, month, date, day, hours, minutes, sec-
onds) are valid and stable, it is necessary to read these registers twice. If the data is the same
both times, then it is valid. Therefore, a minimum of two and a maximum of three accesses are
required.
The RTC has five programmable fields: month, date, hours, minutes and seconds.
Each of these fields can be enabled or disabled to match the alarm condition:
Depending on the combination of fields enabled, a large number of possibilities are available to
the user ranging from minutes to 365/366 days.
Verification on user interface data is performed when accessing the century, year, month, date,
day, hours, minutes, seconds and alarms. A check is performed on illegal BCD entries such as
illegal date of the month with regard to the year and century configured.
If one of the time fields is not correct, the data is not loaded into the register/counter and a flag is
set in the validity register. The user can not reset this flag. It is reset as soon as an acceptable
value is programmed. This avoids any further side effects in the hardware. The same procedure
is done for the alarm.
The following checks are performed:
• If all the fields are enabled, an alarm flag is generated (the corresponding flag is asserted
• If only the “seconds” field is enabled, then an alarm is generated every minute.
1. Century (check if it is in range 19 - 20)
2. Year (BCD entry check)
3. Date (check range 01 - 31)
4. Month (check if it is in BCD range 01 - 12, check validity regarding “date”)
and an interrupt generated if enabled) at a given month, date, hour/minute/second.
6289D–ATARM–3-Oct-11