self.init_card_v2()
elif r == (_R1_IDLE_STATE | _R1_ILLEGAL_COMMAND):
self.init_card_v1()
else:
raise OSError("couldn't determine SD card version")
# get the number of sectors
# CMD9: response R2 (R1 byte + 16-byte block read)
if self.cmd(9, 0, 0, 0, False) != 0:
raise OSError("no response from SD card")
csd = bytearray(16)
self.readinto(csd)
if csd[0] & 0xC0 == 0x40: # CSD version 2.0
self.sectors = ((csd[8] << 8 | csd[9]) + 1) * 1024
elif csd[0] & 0xC0 == 0x00: # CSD version 1.0 (old, <=2GB)
c_size = (csd[6] & 0b11) << 10 | csd[7] << 2 | csd[8] >> 6
c_size_mult = (csd[9] & 0b11) << 1 | csd[10] >> 7
read_bl_len = csd[5] & 0b1111
capacity = (c_size + 1) * (2 ** (c_size_mult + 2)) * (2**read_bl_len)
self.sectors = capacity // 512
else:
raise OSError("SD card CSD format not supported")
# print('sectors', self.sectors)
# CMD16: set block length to 512 bytes
if self.cmd(16, 512, 0) != 0:
raise OSError("can't set 512 block size")
# set to high data rate now that it's initialised
self.init_spi(baudrate)
def init_card_v1(self):
for i in range(_CMD_TIMEOUT):
self.cmd(55, 0, 0)
if self.cmd(41, 0, 0) == 0:
# SDSC card, uses byte addressing in read/write/erase commands
self.cdv = 512
# print("[SDCard] v1 card")
return
raise OSError("timeout waiting for v1 card")
def init_card_v2(self):
for i in range(_CMD_TIMEOUT):
time.sleep_ms(50)
self.cmd(58, 0, 0, 4)
self.cmd(55, 0, 0)
if self.cmd(41, 0x40000000, 0) == 0:
self.cmd(58, 0, 0, -4) # 4-byte response, negative means keep the first byte
ocr = self.tokenbuf[0] # get first byte of response, which is OCR
if not ocr & 0x40:
# SDSC card, uses byte addressing in read/write/erase commands
self.cdv = 512
else:
# SDHC/SDXC card, uses block addressing in read/write/erase commands
self.cdv = 1
# print("[SDCard] v2 card")
return
raise OSError("timeout waiting for v2 card")
def cmd(self, cmd, arg, crc, final=0, release=True, skip1=False):
self.cs(0)
# create and send the command
buf = self.cmdbuf
buf[0] = 0x40 | cmd
buf[1] = arg >> 24
buf[2] = arg >> 16
buf[3] = arg >> 8
buf[4] = arg
buf[5] = crc
self.spi.write(buf)
if skip1:
self.spi.readinto(self.tokenbuf, 0xFF)
# wait for the response (response[7] == 0)
for i in range(_CMD_TIMEOUT):
self.spi.readinto(self.tokenbuf, 0xFF)
response = self.tokenbuf[0]
if not (response & 0x80):
# this could be a big-endian integer that we are getting here
# if final<0 then store the first byte to tokenbuf and discard the rest
if final < 0:
self.spi.readinto(self.tokenbuf, 0xFF)
final = -1 - final
for j in range(final):
self.spi.write(b"\xff")
if release:
self.cs(1)
self.spi.write(b"\xff")
return response
# timeout
self.cs(1)
self.spi.write(b"\xff")
return -1
def readinto(self, buf):
self.cs(0)
# read until start byte (0xff)
for i in range(_CMD_TIMEOUT):
self.spi.readinto(self.tokenbuf, 0xFF)
if self.tokenbuf[0] == _TOKEN_DATA:
break
time.sleep_ms(1)
else:
self.cs(1)
raise OSError("timeout waiting for response")
# read data
mv = self.dummybuf_memoryview
if len(buf) != len(mv):
mv = mv[: len(buf)]
self.spi.write_readinto(mv, buf)
# read checksum
self.spi.write(b"\xff")
self.spi.write(b"\xff")
self.cs(1)
self.spi.write(b"\xff")
def write(self, token, buf):
self.cs(0)
# send: start of block, data, checksum
self.spi.read(1, token)
self.spi.write(buf)
self.spi.write(b"\xff")
self.spi.write(b"\xff")
# check the response
if (self.spi.read(1, 0xFF)[0] & 0x1F) != 0x05:
self.cs(1)
self.spi.write(b"\xff")
return
# wait for write to finish
while self.spi.read(1, 0xFF)[0] == 0:
pass
self.cs(1)
self.spi.write(b"\xff")
def write_token(self, token):
self.cs(0)
self.spi.read(1, token)
self.spi.write(b"\xff")
# wait for write to finish
while self.spi.read(1, 0xFF)[0] == 0x00:
pass
self.cs(1)
self.spi.write(b"\xff")
def readblocks(self, block_num, buf):
nblocks = len(buf) // 512
assert nblocks and not len(buf) % 512, "Buffer length is invalid"
if nblocks == 1:
# CMD17: set read address for single block
if self.cmd(17, block_num * self.cdv, 0, release=False) != 0:
# release the card
self.cs(1)
raise OSError(5) # EIO
# receive the data and release card
self.readinto(buf)
else:
# CMD18: set read address for multiple blocks
if self.cmd(18, block_num * self.cdv, 0, release=False) != 0:
# release the card
self.cs(1)
raise OSError(5) # EIO
offset = 0
mv = memoryview(buf)
while nblocks:
# receive the data and release card
self.readinto(mv[offset : offset + 512])
offset += 512
nblocks -= 1
if self.cmd(12, 0, 0xFF, skip1=True):
raise OSError(5) # EIO
def writeblocks(self, block_num, buf):
nblocks, err = divmod(len(buf), 512)
assert nblocks and not err, "Buffer length is invalid"
if nblocks == 1:
# CMD24: set write address for single block
if self.cmd(24, block_num * self.cdv, 0) != 0:
raise OSError(5) # EIO
# send the data
self.write(_TOKEN_DATA, buf)
else:
# CMD25: set write address for first block
if self.cmd(25, block_num * self.cdv, 0) != 0:
raise OSError(5) # EIO
# send the data
offset = 0
mv = memoryview(buf)
while nblocks:
self.write(_TOKEN_CMD25, mv[offset : offset + 512])
offset += 512
nblocks -= 1
self.write_token(_TOKEN_STOP_TRAN)
def ioctl(self, op, arg):
if op == 4: # get number of blocks
return self.sectors
if op == 5: # get block size in bytes
return 512
**五、检查SD卡是否挂载成功代码**
from machine import Pin,SPI from sdcard import SDCard import time,os,esp
cs = Pin(5,Pin.OUT) spi = SPI(2,sck = Pin(18),mosi = Pin(23),miso = Pin(19)) sd = SDCard(spi,cs)
def main(): os.VfsFat(sd) os.mount(sd,"/sd") # 挂载SD卡
fb = os.statvfs('/sd')
print("SD capacity = %d B %d M"%(fb[0] * fb[2],fb[0] * fb[2]/1024/1024))
print("SD Remaining = %d B %d M"%(fb[0] * fb[3],fb[0] * fb[3]/1024/1024))
print("esp32 Flash容量: %d M"%(esp.flash_size()/1024/1024))
while True:
pass
if name == "main": main()
演示效果：
**六、示例代码**
from machine import Pin,SPI from sdcard import SDCard import time,os,esp
cs = Pin(5,Pin.OUT) spi = SPI(2,sck = Pin(18),mosi = Pin(23),miso = Pin(19)) sd = SDCard(spi,cs)
def main(): os.VfsFat(sd) # 创建一个使用 FAT 文件系统格式的文件系统对象。 os.mount(sd,"/sd") # 挂载SD卡
fb = os.statvfs('/sd') # 获取文件系统的状态。
print("SD capacity = %d B %d M"%(fb[0] * fb[2],fb[0] * fb[2]/1024/1024))
print("SD Remaining = %d B %d M"%(fb[0] * fb[3],fb[0] * fb[3]/1024/1024))
print("esp32 Flash容量: %d M"%(esp.flash_size()/1024/1024))
# 获取文件或目录的状态，若不存就创建
try:
os.stat("/sd/Hi") # 获取文件或目录的状态。
except:
os.mkdir("/sd/Hi") # 创建目录
#os.rmdir("/sd/Hi") # 删除目录
print(os.listdir("/sd")) # os.listdir不带参数，列出当前目录。否则列出给定的目录
# 写操作
w = open("/sd/Hi/text.txt",'w',encoding="utf-8")
w.write("Welcome to China!")
w.close()
print(os.listdir("/sd/Hi"))
# 读操作
r = open("/sd/Hi/text.txt",'r',encoding="utf-8")
text = r.read() # f.read()直接读取全部文件
r.close()
print(text)
r = open("/sd/Hi/text.txt",'r',encoding="utf-8")
text = r.read().split() # r.read().split()把文件内容当成一个列表返回
r.close()
print(text)
for chine in text:
print(chine)
for number in range(len(text)):
print(text[number])
for i in range(10):
w = open("/sd/Hi/number.txt",'w',encoding="utf-8")
w.write("%.3d"%i)
w.close()
r = open("/sd/Hi/number.txt",'r',encoding="utf-8")
num = r.read()
r.close()
#print("number = %s"%num)
print("number = %.3d"%(int(num)))
time.sleep(0.01)
os.umount("/sd") # 卸载SD卡
while True:
pass
if name == "main": main()
示例效果：
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