Motorola MPC8260 - Manual (Page 208)

6-6 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part III. The Hardware Interface
WT
BADDR30
IRQ3
Write throughÑOutput used for L2 cache control. For each core-initiated MPC8260 60x
transaction, the state of this pin indicates if the transaction should be cached using write-through or
copy-back mode. Assertion of WT indicates that the transaction should be cached using the
write-through mode.
Burst address 30ÑThere are Þve burst address output pins. These pins are outputs of the 60x
memory controller. These pins are used in external master conÞguration and are connected directly
to memory devices controlled by MPC8260Õs memory controller.
Interrupt request 3ÑThis input is one of the eight external lines that can request (by means of the
internal interrupt controller) a service routine from the core.
L2_HIT
IRQ4
L2 cache hitÑ(Input). It is used for L2 cache control. Assertion of this pin indicates that the 60x
transaction will be handled by the L2 cache. In this case, the memory controller will not start an
access to the memory it controls.
Interrupt request 4ÑThis input is one of the eight external lines that can request (by means of the
internal interrupt controller) a service routine from the core.
CPU_BG
BADDR31
IRQ5
CPU bus grantÑ(Output) The value of the 60x core bus grant is driven on this pin for the use of an
external MPC2605GA L2 cache. The driven bus grant is non qualiÞed, that is, in case of external
arbiter the user should qualify this signal with the bus grant input to the MPC8260 before
connecting it to the L2 cache.
Burst address 31ÑThere are Þve burst address output of the 60x memory controller used in
external master conÞguration and are connected directly to the memory devices controlled by
MPC8260Õs memory controller.
Interrupt Request 5ÑThis input is one of the eight external lines that can request (by means of the
internal interrupt controller) a service routine from the core.
CPU_DBG CPU bus data bus grantÑ(Output) The value of the 60x core data bus grant is driven on this pin for
the use of an external MPC2605GA L2 cache.
CPU_DBG CPU data bus grantÑ(Output). The OR of all data bus grant signals for internal masters from the
internal arbiter is driven on CPU_DBG. CPU_DBG should be connected to the CPU_DBG input of
an external MPC2605GA L2 cache if the internal arbiter is used (BCR[EARB] = 0). If an external
arbiter is used in this MPC8260, the CPU_DBG input of the L2 cache should be connected to the
DBG driven from the external arbiter to this MPC8260.
CPU_BR CPU bus requestÑ(Output) The value of the 60x core bus request is driven on this pin for the use
of an external MPC2605GA L2 cache.
CS[0Ð9] Chip selectÑThese are output pins that enable speciÞc memory devices or peripherals connected
to MPC8260 buses.
CS[10]
BCTL1
DBG_DIS
Chip selectÑThese are output pins that enable speciÞc memory devices or peripherals connected
to MPC8260 buses.
Buffer control 1ÑOutput signal whose its function is controlling buffers on the 60x data bus. Usually
used with BCTL0. The exact function of this pin is deÞned by the value of SIUMCR[BCTLC]. See
Section 4.3.2.6, ÒSIU Module ConÞguration Register (SIUMCR),Ó for details.
Data bus grant disableÑThis is an output when the MPC8260 is in external arbiter mode and an
input when the MPC8260 is in internal arbiter mode. When this pin is asserted, the 60x bus arbiter
should negate all of its DBG outputs to prevent data bus contention.
CS[11]
AP[0]
Chip selectÑOutput that enable speciÞc memory devices or peripherals connected to MPC8260
buses.
Address parity 0Ñ(Input/output)The 60x master that drives the address bus, drives also the
address parity signals. The value driven on address parity 0 pin should give odd parity (odd number
of Ô1Õs) on the group of signals that includes address parity 0 and A[0Ð7].
Table 6-1. External Signals (Continued)
Signal Description