A .Flash
1. Built-in Flash programming access
(1) In the erase and write flash must be unlocked, locked after operation
FLASH_Unlock (); // unlock
FLASH_Lock (); // lock
Before (2) read / write Flash should clear the error identification
FLASH_ClearFlag(FLASH_FLAG_EOP|FLASH_FLAG_OPERR|FLASH_FLAG_WRPERR|
FLASH_FLAG_PGAERR|FLASH_FLAG_PGPERR|FLASH_FLAG_PGSERR);
(3) erase and write operations
FLASH_Status FLASH_EraseSector(uint32_t FLASH_Sector, uint8_t VoltageRange)
parameter:
FLASH_Sector - which sector
VoltageRange - voltage range
Return FLASH_COMPLETE expressed erase success
FLASH_Status FLASH_ProgramWord(uint32_t Address, uint32_t Data)
parameter:
Address - the address written
Date - write data
Indicates a write successful return FLASH_COMPLETE
(4) Read Operation
Flash read operation is very simple, direct address to be read as a Flash memory addresses to access it
Exercise:
Read the temperature via Bluetooth, the storage temperature and reading time to flash
Two .SPI
1. Concept and bus structures,
SPI Serial Peripheral interface is an abbreviation, is the serial peripheral interface. Motorola is designed. SPI interface communication between the main clock used in eeprom flash rtc AD converter, a digital signal processor, etc., and CPU peripherals
The SPI is a high-speed, full-duplex, synchronous serial bus (from a multi-master), data transmission requires four wires
SDI: Serial Data Input
SDO: Serial Data Output
SCK: clock line
CS: From the device is enabled
To distinguish the direction of transmission of the master and slave devices, we generally named in the following manner
MISO (master input slave output): master input, slave output
MOSI (master output slave input): master output, slave input
SCLK: clock signal line, the main control device
CS: chip select signal from the line, the main control device
2. Communication principle
Transmission timing IO ports may be used an analog implementation may be implemented using the SPI Controller
3. The clock phase and polarity
(1) Clock Polarity
The default level decision clock line
CPOL = 1 default high
Low default CPOL = 0
(2) Clock Phase
Several edge decision reader
CPHA = 1 sampled at the second edge
CPHA = 0 is sampled at a first edge
4.stm32f407 of SPI controller
Three .SPI Flash -------- W25Q128
1. Schematic
2.w25q128 instruction manual
(1) a high order position and polarity
MSB
mode = 0 (the default level)
mode = 1 (default high level)
Rising input falling output
(2) Status register 1 and 2
(3) operation of the chip
3.SPI Controller Programming
(1) Open GPIO clock and SPI
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
....
(2) configured to multiplex the GPIO function (chip select pin is configured as output)
GPIO_Init (...);
(3) The IO port multiplexed and mapped to the SPI function
GPIO_PinAFConfig (GPIOB, GPIO_PinSource3, GPIO_AF_SPI1);
GPIO_PinAFConfig (GPIOB, GPIO_PinSource4, GPIO_AF_SPI1);
GPIO_PinAFConfig (GPIOB, GPIO_PinSource4, GPIO_AF_SPI1);
(4) SPI Initialization
void SPI_Init(SPI_TypeDef* SPIx, SPI_InitTypeDef* SPI_InitStruct)
parameter:
SPIx - which SPI
SPI_InitStruct - initialization structure
| struct typedef uint16_t SPI_Mode;! / * <master / slave mode SPI_Mode_Master @ref SPI_mode * / uint16_t SPI_DataSize;! / * <data length SPI_DataSize_8b @ref SPI_data_size * / uint16_t SPI_CPOL; /*!< 极性 SPI_CPOL_Low ？ @ref SPI_Clock_Polarity */ uint16_t SPI_CPHA; /*!< 相位 SPI_CPHA_1Edge ？@ref SPI_Clock_Phase */ uint16_t SPI_NSS;! / * <Chip Select * SPI_Slave_Select_management @ref selected SPI_NSS_Soft / uint16_t SPI_FirstBit;! / * <high position in order SPI_FirstBit_MSB * / uint16_t SPI_CRCPolynomial;! / * <CRC check is not used * / |
(5) Enable SPI1
SPI_Cmd(SPI1,ENABLE);
(6) transmitting and receiving data
uint16_t SPI_I2S_ReceiveData(SPI_TypeDef* SPIx)
void SPI_I2S_SendData(SPI_TypeDef* SPIx, uint16_t Data)
(7) transmission status query
FlagStatus SPI_I2S_GetFlagStatus(SPI_TypeDef* SPIx, uint16_t SPI_I2S_FLAG)
Note: SPI transmit and receive functions for
u8 xxx(u8 data)
{
// Wait transmit buffer is empty
while(SPI_I2S_GetFlagStatus(...)...);
//send data
SPI_I2S_SendData(.....);
// synchronize the received data reception waiting
while(SPI_I2S_GetFlagStatus(...)...);
//Receive data
return SPI_I2S_ReceiveData(...);
}
Note: SPI and the communication device is selected from the sheet before the election
Down before communication chip select
Communication is completed chip select pulled