Motorola MVME2300 Series manual Data Path for Reads from the Falcon Internal CSRs

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Falcon ECC Memory Controller Chip Set

Accesses to the CSR are mapped differently depending on whether they are reads or writes. For reads, CSR data read on the upper half of the data bus comes from the upper Falcon while CSR data read on the lower half of the data bus comes from the lower Falcon. (See Figure 3-4.)

MPC60x Master

Upper Data Bus Lower Data Bus

CSR	CSR
Upper FALCON	Lower FALCON

1903 9609

Figure 3-4. Data Path for Reads from the Falcon Internal CSRs

For writes, internal register or test SRAM data written on the upper half of the data bus goes to the upper Falcon and is automatically copied by hardware to the lower Falcon. Internal register or test SRAM data written on the lower half of the data bus does not go to either Falcon in the pair, but the access is terminated normally with TA_. (See Figure 3-5.)

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