PIC32_RTCCON
writel(PIC32_RTCCON_ON, base + PIC32_CLR(PIC32_RTCCON));
writel(PIC32_RTCCON_RTCWREN, base + PIC32_SET(PIC32_RTCCON));
writel(3 << 9, base + PIC32_CLR(PIC32_RTCCON));
if (!(readl(base + PIC32_RTCCON) & PIC32_RTCCON_ON))
writel(PIC32_RTCCON_ON, base + PIC32_SET(PIC32_RTCCON));