Problems with counting time intervals & SD performance

edesign · September 15, 2020, 5:07pm

Greetings!
I tested the MicroSD cards that I found. Slightly changed the program for correct time tracking, using the hardware RTC. I would be very grateful to fix the work of millis () and tick_ms () in the future.
It was very unexpected to find that MicroSDXC cards with exFAT also work, although I have met somewhere on the forum that only SDHC cards up to 32Gb work. I ran the test program from the IDE, actually from RAM. 32 KB blocks were used for the exchange.
If the driver of exchange with the card is improved, I can also make a new test.

import pyb, machine, utime, sensor, image, gc, uos

LED_RED = 1
LED_GREEN = 2
LED_BLUE = 3
LED_IR = 4

BLOCK_SIZE = 512
NUM_BLOCKS = 64 # 32768 Bytes

def SD_WR_Test():
    # Synchronization operation
    uos.sync()
    # Create file
    f = open('/data.txt','wb')
    bytes = 0
    #time_start = utime.ticks_ms()
    #time_start = pyb.millis()
    time_rtc_start = rtc.datetime()
    for n in range(1, 10000):
        bytes += f.write(fill_string)
    #time_end = utime.ticks_ms()
    #time_end = pyb.millis()
    time_rtc_stop = rtc.datetime()
    f.close()
    #time_operation = (time_end - time_start)/1000.0
    time_operation = (time_rtc_stop[5] * 60.0 + time_rtc_stop[6] + (1.0 - time_rtc_stop[7] / 256.0)) - \
        (time_rtc_start[5] * 60.0 + time_rtc_start[6] + (1.0 - time_rtc_start[7] / 256.0))
    speed = bytes / time_operation
    print("Write to SD: {} bytes, in time: {:.3f} sec, Speed: {:.3f} KBytes/sec".format(bytes, time_operation, speed / 1024))

def SD_RD_Test():
    gc.collect()
    buffer = bytearray(BLOCK_SIZE * NUM_BLOCKS)
    # Open file in binary read mode
    f = open('/data.txt','rb')
    bytes = 0
    #time_start = utime.ticks_ms()
    #time_start = pyb.millis()
    time_rtc_start = rtc.datetime()
    for n in range(1, 10000):
        bytes += f.readinto(buffer)
    #time_end = utime.ticks_ms()
    #time_end = pyb.millis()
    time_rtc_stop = rtc.datetime()
    f.close()
    #time_operation = (time_end - time_start)/1000.0
    time_operation = (time_rtc_stop[5] * 60.0 + time_rtc_stop[6] + (1.0 - time_rtc_stop[7] / 256.0)) - \
        (time_rtc_start[5] * 60.0 + time_rtc_start[6] + (1.0 - time_rtc_start[7] / 256.0))
    speed = bytes / time_operation
    print("Read from SD: {} bytes, in time: {:.3f} sec, Speed: {:.3f} KBytes/sec".format(bytes, time_operation, speed / 1024))
    # Remove file
    uos.remove('/data.txt')


# Main
pyb.LED(LED_RED).on()

rtc = pyb.RTC()
# Any time base (year, month, day, weekday, hours, minutes, seconds, subseconds)
rtc.datetime((2014, 5, 1, 4, 13, 0, 0, 0))
pyb.delay(1000)

gc.collect()
print("Start testing ...")
print("Free heap memory: {} bytes".format(gc.mem_free()))
print("Statvfs info: {}".format(uos.statvfs('/')))

fill_string = 'A' * BLOCK_SIZE * NUM_BLOCKS
SD_WR_Test()
SD_RD_Test()

print("Completed ! \r\n")
pyb.LED(LED_RED).off()

while(True):
    pass

FINAL RESULTS:

Old cards and not working

Kingston 1Gb “MicroSD” [SDC/1GB-2P1A] Declared: - old card, but not used
Statvfs info: (16384, 16384, 62855, 62855, 62855, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 88.797 sec, Speed: 3603.370 KBytes/sec
Read from SD: 327647232 bytes, in time: 22.875 sec, Speed: 13987.671 KBytes/sec

SanDisk Ultra 8 Gb “UHS-I U1” [SDSDQUAN-008G-G4A] Declared: “SPEED up to 30 MBs”
OLD CARD NOT WORK WITH OPENMV, BUT ON PC WORKS WELL !!!

microSDHC / UHS-I Class 10

ADATA Premier 8 Gb “UHS-I Class10” [AUSDH8GUICL10-R] Declared: Write 10 MBs, Read 50 MBs
Statvfs info: (32768, 32768, 236768, 236764, 236764, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 35.816 sec, Speed: 8933.559 KBytes/sec
Read from SD: 327647232 bytes, in time: 17.832 sec, Speed: 17943.440 KBytes/sec

ADATA Premier 16 Gb “UHS-I Class10” [AUSDH16GUICL10-R] Declared: Write 10 MBs, Read 50 MBs
Statvfs info: (32768, 32768, 483040, 483039, 483039, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 40.754 sec, Speed: 7851.223 KBytes/sec
Read from SD: 327647232 bytes, in time: 16.359 sec, Speed: 19558.693 KBytes/sec

SanDisk Ultra 16 Gb “UHS-I Class10” [SDSQUNS-016G-GN3MA] Declared: Write 10 MBs, Read 80 MBs
Statvfs info: (32768, 32768, 473472, 473471, 473471, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 44.402 sec, Speed: 7206.106 KBytes/sec
Read from SD: 327647232 bytes, in time: 25.723 sec, Speed: 12439.150 KBytes/sec

SanDisk Ultra 32 Gb “UHS-I Class10” [SDSQUNS-032G-GN3MN] Declared: Write 10 MBs, Read 80 MBs
Statvfs info: (32768, 32768, 973584, 963582, 963582, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 30.758 sec, Speed: 10402.820 KBytes/sec
Read from SD: 327647232 bytes, in time: 16.578 sec, Speed: 19300.614 KBytes/sec

Transcend Premium 16Gb “UHS-I Class10 200x” [TS16GUSDC10] Declared: Write 10 MBs, Read 30 MBs
Statvfs info: (32768, 32768, 485936, 367978, 367978, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 40.570 sec, Speed: 7886.752 KBytes/sec
Read from SD: 327647232 bytes, in time: 16.734 sec, Speed: 19120.403 KBytes/sec

microSDHC / UHS-I U1

Mirex 32Gb “UHS-I U1 Class10” [13613-ADSUHS32] Declared: Write 45 MBs, Read 104 MBs
Statvfs info: (32768, 32768, 953824, 953823, 953823, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 35.543 sec, Speed: 9002.287 KBytes/sec
Read from SD: 327647232 bytes, in time: 15.789 sec, Speed: 20265.167 KBytes/sec

Qumo 32Gb “UHS-I U1 Class10” [QM32GMICSDHC10U1] Declared: Write 10 MBs, Read 90 MBs
Statvfs info: (32768, 32768, 953792, 947937, 947937, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 35.164 sec, Speed: 9099.290 KBytes/sec
Read from SD: 327647232 bytes, in time: 15.512 sec, Speed: 20627.501 KBytes/sec

Smartbuy 32 Gb “UHS-I U1 Class10” [SB32GBSDCL10-01] Declared: Write 20 MBs, Read 40 MBs
Statvfs info: (32768, 32768, 966016, 956015, 956015, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 44.398 sec, Speed: 7206.740 KBytes/sec
Read from SD: 327647232 bytes, in time: 17.594 sec, Speed: 18186.459 KBytes/sec

Transcend Premium 8 Gb “UHS-I U1 Class10 400x” [TS8GUSDU1] Declared: Write 10 MBs, Read 60 MBs
Statvfs info: (32768, 32768, 239328, 233135, 233135, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 33.781 sec, Speed: 9471.763 KBytes/sec
Read from SD: 327647232 bytes, in time: 16.246 sec, Speed: 19695.072 KBytes/sec

microSDHC / UHS-I U3

Kingston Canvas React microSDHC 32 Gb “UHS-I U3 A1 V30” [SDCR/32GBSP] Declared: Write 70 MBs, Read 100 MBs
Statvfs info: (32768, 32768, 948864, 948863, 948863, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 30.723 sec, Speed: 10414.724 KBytes/sec
Read from SD: 327647232 bytes, in time: 18.867 sec, Speed: 16958.966 KBytes/sec

Panasonic 16 Gb “UHS-I U3 Class10” [RP-SMGB16GAK] Declared: Write 45 MBs, Read 95 MBs
Statvfs info: (32768, 32768, 488704, 488701, 488701, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 31.602 sec, Speed: 10125.070 KBytes/sec
Read from SD: 327647232 bytes, in time: 20.766 sec, Speed: 15408.542 KBytes/sec

Sandisk Extreme 32 Gb “UHC-I U3” [SDSQXNE-032G-GN6AA] Declared: Write 40 MBs, Read 90 MBs
Statvfs info: (32768, 32768, 973584, 963584, 963584, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 28.898 sec, Speed: 11072.155 KBytes/sec
Read from SD: 327647232 bytes, in time: 16.809 sec, Speed: 19035.976 KBytes/sec

Sony 16 Gb “UHC-I U3 95Mbs” [SR-16UX2] Declared: Write 60 MBs, Read 95 MBs
Statvfs info: (32768, 32768, 493280, 491059, 491059, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 26.391 sec, Speed: 12124.305 KBytes/sec
Read from SD: 327647232 bytes, in time: 16.438 sec, Speed: 19465.734 KBytes/sec

microSDXC / UHS-I U1 & U3

Sandisk Extreme 64 Gb “UHC-I U3 A1 V30” [SDSQXAF-064G-GN6MA] Declared: Write 60 MBs, Read 100 MBs
Statvfs info: (131072, 131072, 486992, 484419, 484419, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 24.492 sec, Speed: 13064.084 KBytes/sec
Read from SD: 327647232 bytes, in time: 16.109 sec, Speed: 19862.223 KBytes/sec

SanDisk Ultra 256 Gb “UHS-I U1 A1” [SDSQUAR-256G-GN6MA] Declared: Write 10-20 MBs, Read 100 MBs (One)
Statvfs info: (262144, 262144, 975808, 975805, 975805, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 29.207 sec, Speed: 10955.169 KBytes/sec
Read from SD: 327647232 bytes, in time: 16.785 sec, Speed: 19062.556 KBytes/sec

SanDisk Ultra 256 Gb “UHS-I U1 A1” [SDSQUAR-256G-GN6MA] Declared: Write 10-20 MBs, Read 100 MBs (Two)
Statvfs info: (262144, 262144, 975808, 975805, 975805, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 21.160 sec, Speed: 15121.249 KBytes/sec
Read from SD: 327647232 bytes, in time: 16.570 sec, Speed: 19309.713 KBytes/sec

Transcend Ultimate 64 Gb “UHC-I U3 633x” [TS64GUSDU3] Declared: Write 85 MBs, Read 95 MBs
Statvfs info: (131072, 131072, 494328, 360944, 360944, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 43.992 sec, Speed: 7273.291 KBytes/sec
Read from SD: 327647232 bytes, in time: 17.590 sec, Speed: 18190.496 KBytes/sec

microSDHC & microSDXC / UHS-II (UHS-I Compatible)

GoodRam IRPRO 32 Gb “UHS-II U3 V90” [IRP-M9BA-0320R11] Declared: Write 260 MBs, Read 280 MBs
Statvfs info: (32768, 32768, 979584, 979583, 979583, 0, 0, 0, 0, 255)
Write to SD: 327647232 bytes, in time: 19.492 sec, Speed: 16415.191 KBytes/sec
Read from SD: 327647232 bytes, in time: 15.980 sec, Speed: 20022.440 KBytes/sec

Other

Internal flash memory OpenMV4P (32Mb) 100 cycles for file 3.27Mb:
Statvfs info: (4096, 4096, 8183, 8177, 8177, 0, 0, 0, 0, 255)
Write to SD: 3244032 bytes, in time: 32.320 sec, Speed: 98.019 KBytes/sec
Read from SD: 3244032 bytes, in time: 0.066 sec, Speed: 47706.351 KBytes/sec

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Problems with counting time intervals & SD performance

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