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STPCI2GDY Datasheet(PDF) 79 Page - STMicroelectronics |
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STPCI2GDY Datasheet(HTML) 79 Page - STMicroelectronics |
79 / 111 page ![]() DESIGN GUIDELINES Issue 1.0 - July 24, 2002 79/111 6.3.3. SDRAM The STPC provides all the signals for SDRAM control. Up to 128 MBytes of main memory are supported. All Banks must be 64 bits wide. Up to 4 memory banks are available when using 16Mbit devices. Only up to 2 banks can be connected when using 64Mbit and 128Mbit components due to the reallocation of CS2# and CS3# signals. This is described in Table 6-4 and Table 6-5. Graphics memory resides at the beginning of Bank 0. Host memory begins at the top of graphics memory and extends to the top of populated SDRAM. Bank 0 must always be populated. Figure 6-5, Figure 6-6 and Figure 6-7 show some typical implementations. The purpose of the serial resistors is to reduce signal oscillation and EMI by filtering line reflections. The capacitance in Figure 6-5 has a filtering effect too, while it is used for propagation delay compensation in the 2 other figures. Figure 6-5. One Memory Bank with 4 Chips (16-bit) CS0# BA[1:0] MA[12:0] WE# RAS0# DQM[7:0] MCLKI MCLKO DQM[7:6] Reference Knot CAS0# MD[63:48] DQM[5:4] MD[47:32] DQM[3:2] MD[31:16] DQM[1:0] MD[15:0] MD[63:0] MCLKA MCLKB MCLKC MCLKD 10pF Length(MCLKI) = Length(MCLKy) with y = {A,B,C,D} |