主板过SDR不过DDR

会员194966

映泰u8569同时支持DDR和SDR的内存的主板,单插SDR时可以正常使用,但单插DDR时主板测试卡,走码到c1时停;查各内存供电,发现SDR和DDR都为3.3V;那位大哥知道此主板自动切换供电的原理,或有此电路图

会员194569

有跳线的呀

会员139645

内存旁边或中间应该有一下跳线，跳过来就可以了

会员194621

不会自动跳线嘛

会员194966

主板说明书上说是自动切换的，没有发现跳线
主板上的说明：􀀰When you use DDR SDRAM, the memory power will
automatically set to 2.5V.
􀀰When you use SDRAM, the memory power will
automatically set to 3.3V.

会员194966

W255H这块芯片是作什么用的

会员194966

W255H有发烫现象

会员112321

应该有跳线的吧

会员194966

方才量了下主板;
SEL_DDR*选端有电压变化(1 = DDR-ONLY mode.
0 = STANDARD SDRAM mode),但IC部分vdd脚有变化，有的没有变（When SEL_DDR is pulled HIGH or configured for DDR-ONLY mode, pin
4, 5, 6, 7, 10, 11,15, 16, 19, 20, 21, 22, 27, 28, 29, 30, 33, 34, 38, 39,
42, 43, 44 and 45 will be configured as DDR outputs.
Connect VDD3.3_2.5 to a 2.5V power supply in DDR-ONLY mode.
When SEL_DDR is pulled LOW or configured for STANDARD SDRAM
output, pin 4, 5, 6, 7, 10, 11, 15, 16, 19 and 20, 21, 22 will be configured
as STANDARD SDRAM outputs.Pin 27, 28, 29, 30, 33, 34, 38, 39, 42,
43, 44 and 45 will be configured as DDR outputs.
Connect VDD3.3_2.5 to a 3.3V power supply in STANDARD SDRAM
mode.）