MPC8567/MPC8568 Hardware Specifications/Reference Manual Specific FAQs

Document created by Omar Cruz Employee on Jul 31, 2012Last modified by Omar Cruz Employee on Jul 31, 2012
Version 2Show Document
  • View in full screen mode

For MPC8568, local bus has pin LAD [0:31] and LA [27:31]. LAD [0:31] is named as Muxed Data/ Address bus while LA [27:31] as address bus. Can LAD [27:31] be used as address bus in muxed mode using LALE signal?

Yes, you can mux LAD [0:26] and LA [27:31] signals.

For MPC8568, should LA [27:31] be always used as five least-significant address bits for addressing any device on local bus?

LAD[0:31] works in most cases, but you need to be careful in the bursting case since LAD is latched once and fixed, while LA[27:31] increments during the burst. So we recommend LA [27:31] since it always works.

I am using a single 20-A switching supply for both VDD_CA and VDD_CB, and we are considering the same power circuit for the MPC8568 CPU version. Since the MPC8568 is single core, what would be the effect of the 1.1V supply still connected to the VDD_CB pins of the MPC8568?

TVDD_CB pins can be connected to MPC8568, but for minimum power consumption it is recommended to leave these pins not connected. Exact amount of additional power consumption if these pins are connected for MPC8568 is not defined, but it can be as much as maximum power consumption of an additional core.

I would like to vary the core frequency up to the lowest possible value which is 800MHz for MPC8568 (according to the reference manual) via Software. What are the recommended values for lowest possible core frequency and lowest platform frequency?

Recommended value for lowest possible core frequency is 667MHz and that for lowest platform frequency is 600MHz.