CPU Interface Functional Overview
60x Bus Mode
Copyright © 2002 Marvell
CONFIDENTIAL
Doc. No. MV-S300165-00, Rev. A
May 21, 2002, Preliminary
Document Classification: Proprietary Information
Page 17
3.2
60x Bus Mode
The GT-64260A can act as master and slave on the 60x bus. In this mode, the GT-64260A 60x internal arbiter sup-
ports three masters on the bus; two external 60x compatible masters, and an internal 60x master. The GT-64260A
is configured to 60x bus mode by having the AD[7:6] signals sampled to b’00’ at reset de-assertion. The CPU bus
configuration can be read in the CPU Mode register’s (Offset: 0x120) CPUType bits [7:4].
DBG0*
T/S O
When using the GT-64260A
internal arbiter, connect the pri-
mary CPU DBG* pin.
When using an external arbiter,
this pin can be left as not con-
nected (NC).
NOTE
: In single CPU systems
with the internal arbiter
enabled, must be used as CPU
DBG0*.
To avoid unstable
states at reset or
when an external
arbiter is used, a
10K-Ohm Pull-up is
recommended.
BR1*/
GT_DBG*
I
When using single CPU sys-
tems, this pin can be left as not
connected (NC).
When using the GT-64260A
internal arbiter, connect to the
secondary CPU BR* pin.
When using an external arbiter,
connect to the arbiter
GT_DBG* pin.
To avoid unstable
states at reset or in a
single CPU configu-
ration, a 10K-Ohm
Pull-up is recom-
mended.
DBG1*
T/S O
When using an external arbiter
or single CPU systems, this pin
can be left as not connected
(NC).
When using the GT-64260A
internal arbiter, connect to the
secondary CPU DBG* pin.
To avoid unstable
states at reset or
when external arbiter
is used, a 10K-Ohm
Pull-up is recom-
mended.
BG1*/
GT_BR*
T/S O
When using single CPU sys-
tems, this pin can be left as not
connected.
When using the GT-64260A
internal arbiter, connect to the
secondary CPU BG* pin.
When using an external arbiter,
connect to the arbiter GT_BR*
pin.
To avoid unstable
states at reset or
when external arbiter
is used, a 10K-Ohm
Pull-up is recom-
mended.
Table 1:
CPU Interface Pin Information (Continued)
Pin Name
Input/
Output
PowerPC CPU Pin
Connection
Required
External
Resistor
Description