Heart STM32- minimalist channel (Volume)
Chapter 12 SDRAM
Main Material type: W9825G6KH-6I
1_ their experience
- When the need to use large memory to run, typically cache display, it is necessary to use external SDRAM, you may be understood as the memory on the computer ...
1280 * 800 resolution, a cache 1Mb ~ 3Mb, is run inside STM32F4xx can not, then we on the external cache it. - After the power-down of loss of data quickly, ranging from a few seconds to one minute, pay special attention to this characteristic restart immediately use.
- There SRAM and SDRAM points, pins and programs do not work in general use SDRAM common, reason: cost-effective, and more information.
- SDRAM, two features, complex structure, easy to use.
- First of all, multi-pin, initialization code more complicated operation structure, command timing diagram is also very complicated!
- However, after initialization, the simple: as long as the address note (eg: 0xC0000000). Forget about the program may be present.
- As used herein is W9825G6KH-6I, there may be more chips in place, as long as the same parameter
- Li Chong mall single reference price of 15 yuan, 11 yuan Taobao around, do not plan cheaper to buy W9825G6KH-6 about 6 yuan, the model has a tail i, when the pit was a lot on debugging, climb detour ten days !!!
2_ hardware principle
- Timing \ action (not important):! Does not describe, you do not Baidu, as seen in other tutorials are detailed, skip it when I wasted a lot of time, no one told me that it is very important complex timing diagram, the program can not beat the slightest hint of a relationship.
3_ hardware connection
- Schematic
- Pin Description:
4_ program uses
- Step thought
- initialization
- Basic functions
- Normal use