Freescale Semiconductor MPC5200B - Manual (Page 261)

MPC5200B Users Guide, Rev. 1
8-28 Freescale Semiconductor
Memory Controller Registers (MBAR+0x0100:0x010C)
Bit Name Description
0:3 brd2rp Burst Read to Read/Precharge delay. Limiting case is Read to Read.
For DDR, suggested value = 0x4 (BurstLength/2)
For SDR, suggested value = 0x8 (BurstLength)
4:7 bwt2rwp Burst Write to Read/Write/Precharge delay. Limiting case is Write to Precharge.
For DDR, suggested value = 0x6 (BurstLength/2 + t
WR
)
For SDR, suggested value = 0x8 (BurstLength + t WR
- 2)
8:11 brd2wt Burst Read to Read/Write/Precharge delay. Limiting case is Read to Write:
For DDR: CL + burstlength/2 + round trip delay + t
Hz
- 1.5 clk; round up.
If round trip delay = 1 clk and t
Hz
= 0.75 ns:
If CL==2: 2 + 4 + 1 + 0.75ns -1.5 = 5.5clk + 0.75ns, round to 0x6.
If CL==2.5: 2.5 + 4 + 1 + 0.75ns + 1.5 = 6clk + 0.75ns, round to 0x7.
For SDR: CL + burstlength + round trip delay + t
Hz
- 1 clk:
If CL==2: 2 + 8 + 1 + 5.4ns - 1 = 10clk + 5.4ns, round to 0xB.
If CL==3: 3 + 8 + 1 + 5.4ns - 1 = 11clk + 5.4ns, round to 0xC.
12:15 burst_length Write 0x07 (Burst Length - 1)
16:31 — Reserved