Motorola MPC860 PowerQUICC, Руководство пользователя

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MOTOROLA Chapter 16. Memory Controller 16-47
Part IV. Hardware Interface
16.6.4.8 Transfer Acknowledge and Data Sample Control (UTA, DLT3)
During a memory access, the UTA bit of the RAM word controls the state of TA driven by
the UPM. TA is driven on the rising edge of GCLK2_50. Therefore, because TA is also
sampled on the rising edge of GCLK2_50, programming UTA to assert in the RAM word
causes the bus master to sample TA as asserted in the next cycle.
When a read access is handled by the UPM and the UTA bit is 0, the value of the DLT3 bit
in the same RAM word indicates when the data input is sampled by the internal bus master,
assuming that MxMR[GPLx4DIS] = 1.
¥ If G4T4/DLT3 functions as DLT3 and DLT3 = 1 in the RAM word, data is latched
on the falling edge of GCLK2_50 instead of the rising edge, which is normal. This
feature lets the user speed up the memory interface by latching data 1/2 clock early,
which can be useful during burst reads. This feature should be used only in systems
without external synchronous bus devices.
32 bits 256 Kbyte 8 8 A22ÐA29 000
512 Kbyte 9 A21ÐA29
1 Mbyte 10 A20ÐA29
2 Mbyte 11 A19ÐA29
4 Mbyte 12 A18ÐA29
1 Mbyte 9 9 A21ÐA29 001
2 Mbyte 10 A20ÐA29
4 Mbyte 11 A19ÐA29
8 Mbyte 12 A18ÐA29
16 Mbyte 13 A17ÐA29
4 Mbyte 10 10 A20ÐA29 010
8 Mbyte 11 A19ÐA29
16 Mbyte 12 A18ÐA29
32 Mbyte 13 A17ÐA29
64 Mbyte 14 A16ÐA29
16 Mbyte 11 11 A19ÐA29 011
32 Mbyte 12 A18ÐA29
64 Mbyte 13 A17ÐA29
64 Mbyte 12 12 A18ÐA29 100
128 Mbyte 13 A17ÐA29
256 Mbyte 14 A16ÐA29
256 Mbyte 13 13 A17ÐA29 101
Table 16-18. AMA/AMB Definition for DRAM Interface (Continued)
Data Bus
Width
Memory Size
DRAM Address Pin Number
MPC860 Address
Pin Connection
AMx
Row Column