Linux support for MPC859T processor

Dmytro Bablinyuk dmytro.bablinyuk at tait.co.nz
Wed Apr 2 12:31:12 EST 2003


We are trying to find a linux supplier who supports Motorola MPC859T
processor (actually it will be processor from Motorola but our custom
board).
We have contacted MontaVista and we discovered that the nearest
processor they support is MPC860.
Also we discovered that:

An MPC860 based board might be suitable for initial S/W development
purposes as the chip is very similar to the MPC859T we intend to use.
There are 7 variants of the '860 with different cache sizes and serial
communications capabilities.
The main differences between the '860 and the '859T that I am aware of are:

1.    The '860 runs at approximately half the speed of the '859T.
2.    The clocking generator for the 860 would require a different
configuration to the the '859 as a consequence of above.
3.    The '860 has an internal RTC function whereas the '859T does not.
4.    The '859T has a dedicated 10/100Mbps ethernet MAC whereas the '860
has to use the serial communication controllers for ethernet operations.
The available ethernet speeds depend on the particular variant of the '860.
Note some of the '860 variants include a dedicated 10/100Mbps ethernet MAC.
5.     The '859T core operates off a lower voltage (1.8V) for power
saving whereas the '860 core runs off a 3.3V supply.
Consequently the '860 draws approximately 2x the power of the '859T.

Apart from the differing core voltages the '860 and '859T appear to be
pin compatible

* Could somebody please give me an advice on how much S/W work might be
involved in the future to port linux from '860 to '859T based on 1-5
(see above)

* Can you suggest (based on above) any of 7 variants of the '860

Thank you


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