Mpc8540 Real-Time Clock Input; Mpc8540 Lbc Clock Divisor - SMART Embedded Computing MVME3100 Installation And Use Manual

7.14

MPC8540 Real-Time Clock Input

The MPC8540 real-time clock (RTC) input is driven by a 1MHz clock generated by the
control and timers PLD. This provides a fixed clock reference for the RTC that software can
use as a known timing reference. To select this 1MHz clock as the RTC timer reference,
software must set the SEL_TBCLK bit in the MPC8540 HID0 register.
7.15

MPC8540 LBC Clock Divisor

The MPC8540 LBC clock output is used by the control and timers PLD. The LBC clock is
derived from a divide by 2, 4 or 8 ratio of the internal CCB (core complex bus) clock as
determined by the clock ratio register (LCRR[CLKDIV]). For proper operation of the local
bus, CLKDIV must be set for divide by 8, which is the default value. The software must
leave this register configured for divide by 8 during initialization.
MVME3100 Single Board Computer Installation and Use (6806800M28H)
MPC8540 Real-Time Clock Input
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