Z32AN00NW200SG Zilog, Z32AN00NW200SG Datasheet - Page 106

• Manufacturer Part Number: Z32AN00NW200SG
• Description: IC ARM922T MCU 200MHZ 256-BGA
• Manufacturer: Zilog
• Series: Encore!® 32r

Specifications of Z32AN00NW200SG

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 200MHz
• Connectivity: EBI/EMI, IrDA, SmartCard, SPI, UART/USART, USB OTG
• Peripherals: DMA, LCD, Magnetic Card Reader, POR, PWM, WDT
• Number Of I /o: 76
• Program Memory Type: ROMless
• Ram Size: 64K x 8
• Voltage - Supply (vcc/vdd): 1.71 V ~ 3.6 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 256-LBGA
• For Use With: 269-4713 - KIT DEV ENCORE 32 SERIES
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -
• Other names: 269-4717

Z32AN Series Data Sheet
Chapter 11: Real-Time Clock (RTC)
11.1 Real-Time Clock Time/Counter Registers
11.2 RTC Alarm
11.3 RTC Wake
11.4 RTC Oscillator Source
11.5 RTC Battery Backup
11.6 RTC Reset
DS0200-003
The real-time clock (RTC) keeps time by maintaining a count of seconds, minutes, hours, day-of-the-month,
month, and year. The current time is kept in 24-hour format. All count and alarm registers are in binary
format. The calendar operation maintains the correct day of the month and automatically compensates for
leap year.
The RTC has a dedicated power supply and maintains operation through the external battery when main
power is not available. It contains an alarm which can be used to generate an interrupt or to generate a
wake condition.
The time is accessible via a number of RTC registers. The seconds, minutes, hours, day-of-the-month, the
month, and year can be read or written through the RTC_SEC, RTC_MIN, RTC_HRS, RTC_DOM,
RTC_MON, and RTC_YR, respectively.
An additional register, RTC_TIME can be used to read all the time registers in a single 32-bit value.
However, only 6 LSB of the RTC_YR are available in this register.
An alarm can be programmed when the current count matches the alarm set-point registers. Alarm registers
are available for seconds, minutes, hours, day-of-the-month, month, and year. Each alarm register can be
independently enabled in RTC_ACTRL. For example, if the minute and hour alarms are both enabled (while
the seconds, day-of-the-month, the month, and year registers are disabled), the alarm only occurs at the
specified minute and hour. The alarm triggers an interrupt if RTC_CTRL.ALARM_EN is set to ‘1’. When this
occurs, RTC_CTRL.ALARM_STATUS is set to ‘1’.
RTC_CTRL.ALARM_STATUS.
comparison of the alarm value to the time value is done once every second.
Whenever an RTC alarm is generated, a wake indication is also sent to the PMU. For the wake to result in
activation of disabled clocks, the PMU must also be programmed. See section Chapter 3: for more details.
The RTC contains an internal oscillator which must be connected to an external 32.768 kHz crystal. The
crystal must be connected to the RTCXI and RTCXO pins.
The RTC derives its power from system power, when available. When system power is not available, the
RTC derives its power from the battery power supply pin (V
continues driving the oscillator and keeping accurate time while valid power remains on at least one of the
power sources.
The alarm, control and time registers of the RTC are not reset in the event of a system reset.
►Note: All read and write operations to these registers must be followed by a read-verify
operation. In the case of reads, a second read must be executed and verified as equal to the first
read. For writes, the written register must be read back and verified as equal to the expected value.
In both cases, this operation must be repeated until verified as correct. This is due to the
asynchronous nature of the 32 kHz clock relative to the hclk. In rare cases, complete incorrect
values may be read or written. If the RTC APB interface is locked, the RTC cannot be written to.
Alarm value and control registers can be written at any time. The
BAT
It can be cleared by writing a ‘1’ to
). Irrespective of the power source, the RTC
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