M55800A Atmel Corporation, M55800A Datasheet - Page 74

• Manufacturer Part Number: M55800A
• Manufacturer: Atmel Corporation

Specifications of M55800A

• Flash (kbytes): 0 Kbytes
• Pin Count: 176
• Max. Operating Frequency: 33 MHz
• Cpu: ARM7TDMI
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 58
• Ext Interrupts: 58
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Uart: 3
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 72
• Resistive Touch Screen: No
• Dac Channels: 1
• Dac Resolution (bits): 10
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 8
• Self Program Memory: NO
• External Bus Interface: 1
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 3.3/5.0
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

13. RTC: Real-time Clock
13.1
Figure 13-1. RTC Block Diagram
74
Year 2000 Conformity
AT91M5880A
Slow Clock
Peripheral
Advanced
SLCK:
Bus
The AT91M55800A features a Real-time Clock (RTC) peripheral that is designed for very low
power consumption. It combines a complete time-of-day clock with alarm and a two-hundred
year Gregorian calendar, complemented by a programmable periodic interrupt.
The time and calendar values are coded in Binary-Coded Decimal (BCD) format. The time for-
mat can be 24-hour mode or 12-hour mode with an AM/PM indicator.
Updating time and calendar fields and configuring the alarm fields is performed by a parallel cap-
ture on the 32-bit data bus. An entry control is performed to avoid loading registers with
incompatible BCD format data or with an incompatible date according to the current month/
year/century.
The Real-time Clock complies fully with the Year 2000 Conformity Requirements as stated in the
British Standards Institution Document Ref BSI-DISC PD2000-1: “Year 2000 conformity shall
mean that neither performance nor functionality is affected by dates prior to, during and after the
year 2000”.
It has been tested to be compliant with the four associated rules:
The RTC represents the year as a four-digit number (1998, 1999, 2000, 2001, etc.) so that the
century is unambiguously identified, in accordance with Rule 3.
1. No value for current date will cause any interruption in operation.
2. Date-based functionality must behave consistently for dates prior to, during and after
3. In all interfaces and data storage, the century in any date must be specified either
4. Year 2000 must be recognized as a leap year.
year 2000.
explicitly or by unambiguous algorithms or inferencing rules.
32768 Divider
Bus Interface
Control
Entry
Time
Interrupt
Control
Date
RTCIRQ
1745F–ATARM–06-Sep-07
AIC