Nexus Port Controller (NPC)MPC5644A Microcontroller Reference Manual, Rev. 61672 Freescale Semiconductor— The Nexus block reset is controlled with JCOMP, power-on reset, and the TAP state machine.All theses sources are independent of system reset— Power-on-reset status indication during reset via MDO[0] in disabled and reset modes• As some of the pads used for the Nexus interface are multi-voltage pads, the maximum supportedinterface frequency is limited to 40 MHz in some modes. This corresponds to a MCKO clockdivider of 1/2 for system clocks up to 80 MHz, and 1/4 for system clocks > 80 MHz.• Nexus Double Data Rate (DDR) mode is not available in the MPC5644A family of devices.• A control bit in the Nexus port controller, NP_PCR[NEXCFG], is used to control whether theadded signals for full width trace port are routed to the MDO[4:11] signals, or theCAL_MDO[4:11] signals. Although the CAL_MDO[4:11] signals are only available in the 496CSP package, this control bit still needs to be programmed when the device is assembled in anyother package.Table 37-1 shows the maximum trace port frequencies supported in different configurations, aswell as the operation of the NPC_PCR[FPM] and [NEXCFG] control bits.37.1.2 Parameter valuesTable 37-1. Nexus trace port routing and speedPackageMax.traceportMHzPort widthNPC_PCR[FPM]Port routing bitNPC_PCR[NEXCFG]MDO[0:3]usageMDO[4:11]usageCAL_MDO[4:11]usageProduction(176QFP,208BGA,324BGA)80 4 MDO(Narrow, FPM=0)Don’t care Trace portuseI/O use Inactive40 12 MDO(Wide, FPM=1)NEXCFG = 1 Trace portuseDebug/Calpackage(496 CSP)80 4 MDO(Narrow, FPM=0)Don't care I/O use40 12 MDO(Wide, FPM=1)NEXCFG = 1Use MDOTrace portuseTrace port use80 NEXCFG = 0(Default setting)Use CAL_MDOI/O use Trace port useTable 37-2. Parameter valuesParameter Description ValueNPC parametersRPM_MDO (R) Number of MDO pins available in reduced-port mode 4NUM_AUX (X) Number of Nexus devices on the device sharing theNexus auxiliary port (not including the NPC)1NUM_BKPT (B) Number of breakpoint requests coming into the blockfrom Nexus and non-Nexus sources on the device1
