Chip data sheets are often hundreds or even thousands of pages long, and they are all in English. It takes a very long time to read them indiscriminately from beginning to end, and it is not necessarily possible to obtain information that is helpful for designing device drivers.
**The correct way to read the chip data sheet is to quickly and accurately locate useful information, **focus on reading these information and ignore irrelevant content. The following takes the data sheet of S3C6410A as an example to analyze the reading method. In order to reflect the reading process intuitively, the pictures in this section are obtained directly from the screen capture of the data sheet.
Open the data manual of S3C6410A and find that the number of pages is 1378, and it is unrealistic to read from beginning to end.
**Chapter 1 "PRODUCT OVERVIEW" of the S3C6410A data sheet is a must-read. By reading this part, you can know the composition of the entire chip. **This chapter often gives the overall structure diagram of a chip, and gives a concise description of the main modules in the chip. The overall structure diagram of S3C6410A is shown in Figure 2.27 (see page 61 of the data sheet).
Each chapter in chapters 2 to 43 corresponds to a module in the overall structure diagram of S3C6410A . Figure 2.28 is a directory structure diagram of the S3C6410A data manual directly captured from Adobe Acrobat.
Chapter 2 "MemoryMap" (memory mapping) is more critical. It has direct guiding significance for locating the base address corresponding to the memory and peripherals. This part should be read carefully .
Chapters 3 to 34 correspond to the peripherals or bus controllers integrated in the CPU. When writing the driver of a certain interface, you should read them in detail, mainly to analyze data, control, and address registers (generally listed in tables in the data manual) ) access control and the operation process of specific equipment (the steps will be given in the data manual, and some will also give flow charts). For example, in order to write the I2C controller driver of S3C6410A, we need to read in detail the register definition table similar to Figure 2.29 and the operation flow chart in Figure 2.30.
Chapter 44 "ELECTRICAL DATA" (for electrical data, not shown in Figure 2.28), describes the electrical characteristics of the chip, such as voltage, current, and timing, setup time, and hold time requirements in various operating modes . All data sheets will contain similar chapters. This chapter is critical for hardware engineers, but generally speaking, driver engineers do not need to read it.
Chapter 45 "MECHANICAL DATA" (mechanical data) describes the physical characteristics, size and package of the chip. Hardware engineers will draw the chip's package (Footprint) according to this chapter, but driver engineers do not need to read it.