The IPC-RTC-APB is a clock-calendar IP core that keeps track of the ¡§Time of Day¡¨. The core is organized as a series of BCD counters that counts Seconds, Minutes, Hours, Days, Months and Years (Time Units).
The RTC seconds counter time base is generated from a programmable divisor of the system clock. The divisor should be set to generate a 1Hz clock enable signal to the seconds counter. This divisor can also be used to adjust the clock accuracy by periodi-cally adding or subtracting values from the divisor. Calibration accuracy is controlled by software.
Each of the Time Units can be loaded by writing BCD information to the proper Time Unit register. The RTC will immediately load the new time and will continue to count. The Core can also be loaded with an Alarm Compare value for each Time Unit that will generate an interrupt when that Time Unit reaches the compare value. A Repeat Alarm function is also available. When enabled, this function will cause an interrupt at the terminal count of each Time Unit counter. For example, if the Repeat Alarm bit (bit 7 or Seconds Alarm Register) for the Seconds counter is set, the RTC engine will generate an interrupt every second when the counter rolls over from 59 to 00. Testmode bits for each Time Unit counter enable the counter to be clocked by the secondsClk in order to speed testability. This can also be used to incrementally update the RTC.The testRstN bit enables the RTC counters to be reset under software control. Oth-erwise the RTC counters are free running and do not reset upon system reset. The IPC-RTC-APB operates as a slave device on the AMBA APB bus. Each register is accessed by simple APB bus transactions. The IPC-RTC-APB package includes Verilog source and simulation test-benches. The IPC-RTC-APB can also be delivered as an FPGA Netlist for Xilinx, Altera and Actel FPGA.
- ƒ Clock/Calendar (BCD Format)
- - Seconds
- - Minutes
- - Hours
- - Days
- - Months
- - Years
- ƒ Alarm Mode for each ¡§Time Unit¡¨
- ƒ Repeat Alarm Mode for each ¡§Time Unit¡¨
- ƒ AMBA APB Interface
- ƒ Interrupt control for Alarms