SPI Interface
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The document provides a detailed overview of the SPI interface and the specific implementation of the MX25L4005A flash memory, including its memory organization, command operations, and addressing. It covers key operational protocols, such as the necessary steps for reading, writing, and erasing data, as well as the requirements for utilizing different SPI modes. Additionally, it explains the functionality of a related ADC (MCP3008) and its communication through SPI.
![MX25L4005A Addressing (3 byte)
Flash Memory Organization
Page #Sector #Block #
11 01523 18 12 8 7
Offset #
AD1 AD2 AD3
16
Sector Address A[18:12]
MSB LSB
Page Program (0x02)Page Address A[18:8] + Offset A[7:0]
. . .
256 byte
1 page=256 bytes
Sector Erase (0x20)
5
16 pages](https://image.slidesharecdn.com/spidriver-160925025118/85/SPI-Interface-5-320.jpg)
![SPI 操作 - big-banging
ReturnMsg CMD_RDID( uint32 *Identification )
{
uint32 temp;
uint8 gDataBuffer[3];
// Chip select go low to start a flash command
CS_Low();
// Send command
#define FLASH_CMD_RDID 0x9F //RDID (Read Identification)
SendByte( FLASH_CMD_RDID);
// Get manufacturer identification, device identification
gDataBuffer[0] = GetByte( );
gDataBuffer[1] = GetByte( );
gDataBuffer[2] = GetByte( );
// Chip select go high to end a command
CS_High();
// Store identification
temp = gDataBuffer[0];
temp = (temp << 8) | gDataBuffer[1];
*Identification = (temp << 8) | gDataBuffer[2];
// Flash ID:C22013
return FlashOperationSuccess;
}
13](https://image.slidesharecdn.com/spidriver-160925025118/85/SPI-Interface-13-320.jpg)
SPI Interface
- 2. SPI 線路 2 SPI 為一個Ring 結構:要讀資料,必送資料 {dummy byte}
- 3. CPOL: rest state of clock (high or low) CPHA: First or second SCLK transition CPOL,CPHA 用來決定latch 資料的時間點 SPI 模式 3
- 4. Serial Flash (SPI interface) Flash size: 4Mbit 1) 64K Block size (Block Erase) 2) 4K Sector size (Sector Erase, Block_Erase_4K) 3) 256 Byte Page size (Page Program) Single Power Supply Operation • 2.7 to 3.6 volt for read, erase, and program operations SPI Modes : Mode 0 & Mode 1 注意: 1) Flash 要寫入page之前,要先Erase 2) Page Program->"0", Erase -->"1" 3) 傳送順序為 MSB First MX25L4005A 規格 4
- 5. MX25L4005A Addressing (3 byte) Flash Memory Organization Page #Sector #Block # 11 01523 18 12 8 7 Offset # AD1 AD2 AD3 16 Sector Address A[18:12] MSB LSB Page Program (0x02)Page Address A[18:8] + Offset A[7:0] . . . 256 byte 1 page=256 bytes Sector Erase (0x20) 5 16 pages
- 6. Read Status Register (RDSR) 6
- 8. 對於 PP, SE, BE, CE, and WRSR 會改變Flash內容的Command, 都 要先設定WEL bit=1 (in RDSR bit 1), 一旦操作完成後, 它會自動reset (將WEL bit設回0) 操作方法: MX25L4005A 操作方法 CS# goes low sending WREN (0x6); // set WEL=1 CS# goes high CS# goes low sending <CMD>+{Flash Address}+{Data}; //see command table CS# goes high CS# goes low deadline = jiffies + MAX_READY_WAIT_JIFFIES; do { status=sending RDSR(0x5) ; if (!(status & WIP) ) return 0; //判斷是否操作完成 cond_resched(); // 再排程 } while (!time_after_eq(jiffies, deadline)); CS# goes high 8
- 9. Read ID command MX25L4005A FlashID:C22013 C2 20 13 9
- 10. Page Program 送出24 bit Address 決定了寫入位址(page+offset)後, 接著就是在這個page內偱序寫入資料。 因為page size為256 byte, 所以最多只能寫256 Byte, 超過會覆蓋到同page的開頭 10
- 11. write_flash(addr, buf, len) ; 在位址 0x2085, 寫入長度是786 byte時, 該進行何種程序? 假設 Page 為256 bytes Answer:要執行4次Page Program cycle (每次不同的Page address) Quiz 11 addr len page PP(0x2100,256) PP(0x2200,256) PP(0x2300,151) PP(0x2085,123) page offset 0x85
- 12. SPI 操作-big-banging void SendByte( uint8 byte_value ) { uint16 i; uint8 cycle_cnt; cycle_cnt = 8; for( i= 0; i < cycle_cnt; i++ ) { if ( (byte_value & IO_MASK) == 0x80 ){ SI = 1; } else{ SI = 0; } SCLK = 0; byte_value = byte_value << 1; SCLK = 1; } } uint8 GetByte( ) { uint16 i; uint8 cycle_cnt; uint8 data_buf; data_buf = 0; cycle_cnt = 8; for( i= 0; i < cycle_cnt; i++ ) { SCLK = 0; if ( SO == 1 ){ data_buf = (data_buf | (0x80 >> i)); } SCLK = 1; } return data_buf; } SCLK = 1; // init Flash input clock 12 SPI Mode : 3
- 13. SPI 操作 - big-banging ReturnMsg CMD_RDID( uint32 *Identification ) { uint32 temp; uint8 gDataBuffer[3]; // Chip select go low to start a flash command CS_Low(); // Send command #define FLASH_CMD_RDID 0x9F //RDID (Read Identification) SendByte( FLASH_CMD_RDID); // Get manufacturer identification, device identification gDataBuffer[0] = GetByte( ); gDataBuffer[1] = GetByte( ); gDataBuffer[2] = GetByte( ); // Chip select go high to end a command CS_High(); // Store identification temp = gDataBuffer[0]; temp = (temp << 8) | gDataBuffer[1]; *Identification = (temp << 8) | gDataBuffer[2]; // Flash ID:C22013 return FlashOperationSuccess; } 13
- 14. ADC (MCP3008) 2.7V 4-Channel/8-Channel 10-Bit A/D Converters with SPI Serial Interface 4 pseudo-differential input pairs or 8 single-ended inputs
- 16. LSB: 最小刻度 VREF determines the analog input voltage range