Rainbow Electronics DS1386 - Manual (Page 4)

DS1386/1386P
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RAMIFIED TIMEKEEPER REGISTERS
The RAMified Timekeeper has 14 registers, which are 8 bits wide that contain all of the timekeeping,
alarm, and watchdog and control information. The clock, calendar, alarm, and watchdog registers are
memory locations, which contain external (user-accessible) copies of the timekeeping data. The external
copies are independent of internal functions except that they are updated periodically by the simultaneous
transfer of the incremented internal copy (see Figure 1). The Command Register bits are affected by both
internal and external functions. This register will be discussed later. The 8 or 32 kbytes of RAM and the
14 external timekeeping registers are accessed from the external address and data bus. Registers 0, 1, 2,
4, 6, 8, 9, and A contain time of day and date information (see Figure 2). Time of day information is
stored in BCD. Registers 3, 5, and 7 contain the Time of Day Alarm information. Time of Day Alarm
information is stored in BCD. Register B is the Command Register and information in this register is
binary. Registers C and D are the Watchdog Alarm Registers and information, which is stored in these
two registers, is in BCD. Registers E through 1FFF or 7FFF are user bytes and can be used to maintain
data at the user’s discretion.
CLOCK ACCURACY (DIP MODULE)
The DS1386 is guaranteed to keep time accuracy to within ±1 minute per month at 25°C.
CLOCK ACCURACY (POWERCAP MODULE)
The DS1386P and DS9034PCX are each individually tested for accuracy. Once mounted together, the
module is guaranteed to keep time accuracy to within
±1.53 minutes per month (35 ppm) at 25°C.