TC8521AM

The TC8521AM is an 1-chip C-MOS LSI to be used for the real time clock fabricated as the peripheral IC of the microcomputer.The TC8521AM has the crystal oscillation circuit of 32768Hz, the counter for clock and calendar, the alarm function, and the 26 X 4-bit RAM.Since the package is of 18-pin DIP, 20-pin SOP and the battery back-up is possible, the time counting system provided with the non-volatile RAM can be fabricated with the crystal and the battery.

Features of the TC8521AM are:(1)low power dissipation realized by Si-gate CMOS technology; (2)clock function (hr, min, sec, date, day of week, year and leap year) Auto-calendar; (3)clock system of 24-hour or 12-hour (AM/PM) is selectable; (4)±30-sec correction function, Alarm signal, or pulse of 16Hz or 1Hz can be output; (5)built-in 26 X 4-bit RAM; (6)directly connectable with CPU bus; (7)4-bit bidirectional data bus; (8)4-bit address input; (9)capable of battery backup.

The absolute maximum ratings of the TC8521AM can be summarized as:(1)supply voltage:-0.5 to 7.0V;(2)input voltage:-0.5 to Vcc+0.5V;(3)operating temperature:-40to 85;(4)storage temperature:-65 to 125.The absolute maximum ratings are rated values which must not be exceeded during operation, even for an instant. Any one of the ratings must not be exceeded.If any absolute maximum rating is exceeded, a device may break down or its performance may be degraded, causing it to catch fire or explode resulting in injury totheuser.Thus, when designing products which include this device, ensure that no absolute maximum rating value will ever be exceeded.Therefore, when the alarm is required to be output at the same time every day, it is enough only to set the hour and the minute after the alarm reset.When the alarm reset is made, all the contents of the alarm register are cleared to "0".However, when "0" is required to be compared (when "0" is necessary to be individually set at the digits of hour and the minute for example at setting just noon), be sure to write "0".