75XX RTC

The RTC connects through I2C to the FPGA. Typically, the battery-backed real time clock is only set or read in the linuxrc bootup script by the ts7500ctl utility. It is only necessary to read the RTC once per bootup to initialize the Linux time of day. This is done with the command "ts7500ctl --getrtc". To set the RTC time, you simply set the Linux time of day (with e.g. the "date" utility) and then run ts7500ctl --setrtc. RTC's are already set before shipment to atomic UTC time and should hold time within 15 PPM while at room temperature.

WARNING:

Be careful when handling board with a battery inserted -- the battery holder leads are through-hole and should the board be placed on a conductive surface and short the battery leads, the RTC will loose its track of time and need to be reset.