Programming Model

MPC60x Master

Upper Data Bus

Lower Data Bus

CSR

CSR

Upper FALCON

Lower FALCON

 

1904 9609

Figure 3-5. Data Path for Writes to the Falcon Internal CSRs

External register data that is written on the upper data bus goes through the upper Falcon, while data that is written on the lower data bus goes through the lower Falcon. Unlike the internal register set, there is no automatic copying of upper data to lower data for the external register set.

CSR read accesses can have a size of 1, 2, 4, or 8 bytes with any alignment. CSR write accesses are restricted to a size of 1 or 4 bytes and they must be aligned. Some Tester registers are limited to 4-byte only accesses. Figure 3-6through Figure 3-9show the memory maps for the different kinds of access.

3

http://www.motorola.com/computer/literature

3-23

Page 185
Image 185
Motorola MVME2300 Series manual Data Path for Writes to the Falcon Internal CSRs