【正文】 軟件驅(qū)動(dòng)程序也不是非常復(fù)雜。狀態(tài)轉(zhuǎn)換之所以重要是因?yàn)镃S線在微控制器和串行EEPROM之間被用作主要的握手線。}以上我展示了sermem_StopWrite()函數(shù)的執(zhí)行。 0x01)。 // 用來(lái)選擇EEPROM進(jìn)行讀狀態(tài)操作 Spi_select ()。串行EEPROM在它往陣列里保存數(shù)據(jù)時(shí)需要一個(gè)爆發(fā)時(shí)間。，是使用該規(guī)則的一個(gè)測(cè)試程序。Void sermem_WriteBlock (into address, unsigned char *puffin cub)。Void sermem_ReadBlock (into address, unsigned char *puffin cuff)。其中一些具有不同的頁(yè)容量和數(shù)據(jù)//容量Void sermem_Initialize ()。當(dāng)你完成時(shí)，sermem_StopRead()會(huì)被調(diào)用。它也定義了讀和寫操作。如果你在跨越頁(yè)邊界后繼續(xù)寫，那么后面的寫操作將在當(dāng)前頁(yè)循環(huán)并覆蓋以前寫過(guò)的數(shù)據(jù)，那不是你要做的！我已經(jīng)在Image craft ‘C’下寫過(guò)一套規(guī)則，用來(lái)處理處理串行EEPROM的問(wèn)題。微芯片25C640使用32字節(jié)的頁(yè)。在一個(gè)WRITE操作中，升高CS線引起EEPROM存儲(chǔ)數(shù)據(jù)。你的軟件在寫的時(shí)候需要將此考慮進(jìn)去。這是相當(dāng)好的。當(dāng)你選擇了一個(gè)器件后需要將此考慮進(jìn)去。寫入狀態(tài)寄存器需要8bit的格式，等等。命令表你可以發(fā)給串行EEPROM一些為數(shù)不多的命令。連上一個(gè)串行EEPROM太簡(jiǎn)單了，它能添加到幾乎所有的CPU，只要該CPU支持SPI總線。最近我在板子的背面為串行EEPROM添加了一塊地方。對(duì)于我們尤其有趣的是EEPROM陣列（它實(shí)際上是EEPROM存儲(chǔ)單元），狀態(tài)寄存器（保存結(jié)構(gòu)和狀態(tài)信息），當(dāng)然還有頁(yè)鎖存（它是暫時(shí)保存當(dāng)前寫入數(shù)據(jù)的區(qū)域）。8VCC電源線。如果你需要中斷操作來(lái)訪問(wèn)其他SPI總線上的器件，那么該引腳是有用的。CPU輸出的數(shù)據(jù)在此線上隨時(shí)鐘輸出。這適合于當(dāng)你想對(duì)軟件錯(cuò)誤有額外的保護(hù)，或者你打算僅僅從器件讀出。用SPI的術(shù)語(yǔ)，就是Slave Out，它應(yīng)該連接到SPI端口的MISO引腳。這是器件的一個(gè)標(biāo)準(zhǔn)引腳。它們（EEPROM）也有幾種封裝型號(hào)，包括一個(gè)8引腳雙列直插封裝以及SOIC。這些較小的差別很容易在軟件中解決。與此對(duì)應(yīng)，Atmen也有一個(gè)128K字節(jié)的器件。這對(duì)于許多應(yīng)用來(lái)說(shuō)是很合適的。當(dāng)然，存在一些折中。另一方面，一個(gè)有8引腳封裝的串行電擦除可編程存儲(chǔ)器能夠買到。與此比較，一個(gè)較為標(biāo)準(zhǔn)的存儲(chǔ)器將需要地址總線和數(shù)據(jù)總線！操作串行電擦除可編程存儲(chǔ)器所需要的組合邏輯數(shù)量是相當(dāng)?shù)偷?。本文的焦點(diǎn)就是基于SPI（串行外圍接口）的器件。當(dāng)然，你可以給它們中的大多數(shù)掛上外部存儲(chǔ)器，但是，那要做許多工作，而且通常要消耗其他有價(jià)值的資源，僅僅是那些輸入/出引腳使芯片變得有用。}Above I show my implementation of the sermem_StopWrite () function. This functions job is to cause the serial EEPROM to mit a previously transferred page to EEPROM. The function razes the CS line, and then issues a RDSR instruction and loops waiting for the WIP bit to go to zero. Note that the spi_deselect () and spi_select () instructions needed to be there. The state transition is important because the CS line is used as the primary handshake between the micro controller that the serial EEPROM. It signals the start and stop of operations. // The Write in Progress (WIP) flag is bit 1. Wait for it to go low } While (spiting (SERMEM_INST_RDSR) amp。Void sermem_Fill (into address, unsigned char bitewing count)。Void sermem_StartWrite (into address)。Void sermem_StartRead (into address)。 mode, which means you can send up to 1 PAGE of data at a time. The number of bytes in a PAGE depends on the specific part. For example, the Atmen 25128 uses a 64 byte PAGE. The Microchip 25C640 uses a 32 byte PAGE. The idea is that each time the address spans a PAGE boundary, you need to raise the CS line so that the chip can write is page into memory. The key thing to watch for is when the address crosses that page boundary. You can write between one and the PAGE size bytes, which means if you only want to write a single byte that is fine. If you continue to write after crossing the page boundary, then the subsequent writes will wrap around on the current page and overwrite previously written data, which isn39。t use them in my software, but you are certainly wele to use them. On my board, you merely cut the trace on the jumper, and wire up the appropriate pins to a port for control.Table of mandsThere are a small number of mands that you can issue to the serial EEPROM. The following table is a quick summary.Instruction Instruction CodeDescriptionREAD0000 0011Read data from memory array beginning at selected addressWRITE0000 0010Write data to memory array beginning at selected addressWREN0000 0110Set the write enable latch (enable writing)WRDI0000 0100Clear the write enable latch (disable writing)RDSR0000 0101Read status registerWRSR0000 0001Write status registerEach instruction code has its own argument requirements. Read/Write, for example, is followed by an address. Writing the status register requires an 8bit argument, and so on. A plete set of instructions and their formats are available in the data sheet for your particular part. Most of these SPI parts have extremely similar manuals!. This is useful if you have interrupt driven routines that need to access ot