The XT26-series Low Level Driver(LLD) sample codes are useful for programmers to development flash drivers or software applications of XT26-series SPI Nand flash products. The included source codes are ANSI C compliant. Any ANSI C compliant complier can be compiled with these codes. The XT26-series LLD sample codes have been verified under hardware and software platform with cortex-M7 IP core. All the contents of LLD sample code are for reference only. It might contain some unknown problems. XTX will not be liable for any claims or damages due to the use of LLD sample codes.
The following files will be available after extracting the zipped file：
| File Name | File description |
|---|---|
| README.md | Readme file for XTX SPI Nand low level driver |
| XT26_CMD.c | Flash command sequences of flash devices |
| XT26_CMD.h | SPI interface command hex code and function prototype |
| XT26_DEF.h | Definitions of flash devices and program parameters. |
| XT26_TYPE.h | Type definition |
| XT26_HAL_EXAMPLE.c | Hardware Abstraction Layer example Code |
| XT26_HAL_EXAMPLE.h | Hardware Abstraction Layer example Code head file |
The XT26-series SPI flash contains special I/O transfer modes besides traditional SPI mode. These modes are dual and quad mode. Types of function of LLD are introduced at section 3.1 and command mapping at section 3.2.
Include CS_Low(), CS_High(), InsertDummyCycle(), SendByte() and GetByte(). Basic functions are highly hardware dependent. You usually need to modify the functions for different hardwares applications. Please see section 4 for details.
Command function is the major part of LLD. It is used to describe the command sequences of flash commands defined in the datasheet . Normally, the sequences from LLD and datasheet are fully matched. However, please follow the datasheet if any discrepancies. Naming rules of command function are as follows:
LLD_STATUS SPI_NAND_XXX(...);
Where XXX is a command name like RDID, READ, and so on. LLD_STATUS report the execution result of the command. Section 5 describes more about the return messages.
Those commands which are neither basic nand command functions belong to utility functions. Utility function provides some unique functionality to make LLD work smoothly.
As mentioned at section 3.1.b, the command functions are implementation of command sequences defined in the datasheet. In this section, the mapping of command sequence and command function is introduced. Here takes the RDID command as a example.
a. RDID command sequence:
CS# goes low-> send RDID instruction code-> 1byte address->24-bits ID data out on SO->
to end RDID operation can drive CS# to high at any time during data out.
b. RDID command function:
LLD_STATUS SPI_NAND_RDID( uint16 *identification )
{
uint8 gdata_buffer[2];
/* Check flash is busy or not */
if( CheckStatus( SR0_OIP ) != READY ) return LLD_Busy;
FLASH_READ(SPI_NAND_CMD_RDID, 0x00, 0,SIO,1,SIO,gdata_buffer,2);
// Store identification
*identification = (gdata_buffer[0] << 8) | gdata_buffer[1];
return LLD_Success;
}
HAL_STATUS FLASH_READ(uint8 command, uint32 addr, uint8 dummy,uint8 addr_mode,uint8 addr_bytes,uint8 data_mode,uint8 *data_buffer,uint32 length)
{
HAL_STATUS status = HAL_OK;
uint32 data_cycle = 0;
CS_Low();
//Send command
SendByte(command,SIO);
//Send Address
if((addr != ADDRESS_NULL) && (addr_mode != IO_NULL))
{
SendFlashAddr(addr,addr_mode,addr_bytes);
}
//Send Dummy cycle
if(dummy!=0)
{
InsertDummyCycle(dummy);
}
//Receive Data
if(length != 0)
{
for(data_cycle = 0;data_cycle < length;data_cycle++)
{
*(data_buffer+data_cycle) = GetByte(data_mode);
}
}
CS_High();
return status;
}
In this example, the procedures of command sequence and command functionare matched. The other sequences and functions are similar to this example.Feel free to verify the relationship between different commands.
The XT26-series LLD sample codes are verified by Cotex-M7 IP core. And it uses Cotex-M7's GPIO ports to connect flash device. With different target hardware platforms, it is necessary to modify the LLD source codes. In this section,porting notices are introduced. And it is divided into data types, definitions of options and function modification for your references.
For the ability of port LLD to different target system, the length of data type can be modified in the XT26_TYPE.h header file. Please verify these data types before applying.
Basic data type:
typedef unsigned long uint32; /* 32 bit wide */
typedef unsigned int uint16; /* 16 bit wide */
typedef unsigned char uint8; /* 8 bit wide */
typedef unsigned char BOOL; /* 1 bit wide */
There are several definition options available based on the target system.
System option:
#define MCUXXX /* Use XXX as micro-controller */
#define GPIO_SPI /* Use GPIO port to connect flash */
#define XT26XXX /* Flash part name */
As mentioned at section 3.1, basic functions are highly dependent on the hardwares. And some utility functions work the same. These functions should be modified based on different hardware architectures. They are displayed as follows:
void CS_Low();
void CS_High();
void InsertDummyCycle( uint8 dummy_cycle);
void SendByte( uint8 byte_value, uint8 transfer_type );
uint8 GetByte( uint8 transfer_type );
void Initial_Spi();
The command functions return a message for operation result. These messages are helpful for programmers to debug at development stage.
LLD_STATUS SPI_NAND_XXX( ... );
XXX:
Flash command name. Like RDID, READ and so on.
ReturnMsg:
-LLD_Success
Flash command execute successful.
-LLD_Busy
The flash device is busy. Waiting WIP bit clear before next write command.
-LLD_OperationTimeOut
The time period of write register, program or erase data exceed expected
time period.
-LLD_ProgramFailed
Program fail error bit was setted
-LLD_EraseFailed
Erase fail error bit was setted
-LLD_ReadIDFailed
Read ID fail
-LLD_CmdInvalid
Command invalid
-LLD_DataInvalid
Data invalid
-LLD_AddressInvalid
The input address exceeds flash's address space.
-LLD_QuadNotEnable
This flash command needs to set to QE bit before executing.
| Revision | Description | Date |
|---|---|---|
| 1.0 | Initial Release | Feb 26th' 2021 |