SDFat is not working with Adafruit Feather M0

[Dvl-s]

SDFat version=2.2.0 Board : Adafruit Feather M0

is SDFat 2.2.0 supports Adafruit Feather M0?

• Yes then Sdcard begin is failling.
• No then can you suggest what to do to work SDFat with Adafruit Feather M0?

[greiman]

I need more Info since it works on my Feather M0 Adalogger.

Here is the SdInfo example:

SdFat version: 2.2.0

Assuming the SD is the only SPI device. Edit DISABLE_CS_PIN to disable an SPI device.

Assuming the SD chip select pin is: 4 Edit SD_CS_PIN to change the SD chip select pin.

type any character to start init time: 2 ms

Card type: SDHC sdSpecVer: 3.00 HighSpeedMode: true

Manufacturer ID: 0X1B OEM ID: SM Product: 00000 Revision: 1.0 Serial number: 0XE30F5501 Manufacturing date: 10/2015

cardSize: 32010.93 MB (MB = 1,000,000 bytes) flashEraseSize: 128 blocks eraseSingleBlock: true dataAfterErase: ones

OCR: 0XC0FF8000

SD Partition Table part,boot,bgnCHS[3],type,endCHS[3],start,length 1,0X0,0X82,0X3,0X0,0XC,0XFE,0XFF,0XFF,8192,62513152 2,0X0,0X0,0X0,0X0,0X0,0X0,0X0,0X0,0,0 3,0X0,0X0,0X0,0X0,0X0,0X0,0X0,0X0,0,0 4,0X0,0X0,0X0,0X0,0X0,0X0,0X0,0X0,0,0

Scanning FAT, please wait.

Volume is FAT32 sectorsPerCluster: 64 fatStartSector: 9316 dataStartSector: 24576 clusterCount: 976512 freeClusterCount: 976354

One possibility is that Adafruit still allows 24 MHz SCK. Arduino now limits SCK to the recommended 12 MHz. I have optimized the SD card driver and 24 MHz may be be marginal for some SAMD21 chips/boards.

The bench example runs at 24 MHz on my Feather M0 Adalogger. Here are results at 12 and 24 MHz. There is not much difference since the SAMD21 SERCOM SPI has huge gaps between bytes at 24 MHz, Uno is faster at 8MHz.

bench at 12 MHz:

Use a freshly formatted SD for best performance.

Type any character to start FreeStack: 26260 Type is FAT32 Card size: 32.01 GB (GB = 1E9 bytes)

Manufacturer ID: 0X1B OEM ID: SM Product: 00000 Revision: 1.0 Serial number: 0XE30F5501 Manufacturing date: 10/2015

FILE_SIZE_MB = 5 BUF_SIZE = 512 bytes Starting write test, please wait.

write speed and latency speed,max,min,avg KB/Sec,usec,usec,usec 516.26,1007,984,989 516.21,1008,984,989

Starting read test, please wait.

read speed and latency speed,max,min,avg KB/Sec,usec,usec,usec 485.63,1058,1050,1051 485.63,1058,1050,1051

bench at 24 MHz.

Use a freshly formatted SD for best performance.

Type any character to start FreeStack: 26260 Type is FAT32 Card size: 32.01 GB (GB = 1E9 bytes)

Manufacturer ID: 0X1B OEM ID: SM Product: 00000 Revision: 1.0 Serial number: 0XE30F5501 Manufacturing date: 10/2015

FILE_SIZE_MB = 5 BUF_SIZE = 512 bytes Starting write test, please wait.

write speed and latency speed,max,min,avg KB/Sec,usec,usec,usec 609.46,856,832,837 609.38,855,832,837

Starting read test, please wait.

read speed and latency speed,max,min,avg KB/Sec,usec,usec,usec 567.02,902,896,900 567.02,903,895,900

---

[Dvl-s]

SOLVED !

There is problem in SPI clock speed, it is 24MHz by default in Feather M0. so I Just change SD.begin(SD_CS_PIN) to SD.begin(SD_CS_PIN, SD_SCK_MHZ(12)) and code is working good

Thank to @greiman

[greiman]

Adafruit should fix their SAMD driver. It has at least three bugs. Guess I will post issues again.

I know Limor Fried AKA Lady Ada and she is extremely capable but very busy. She has built a business with over 100 employees and is deeply into everything.

Three bugs I know for SAMD21 SPI are:

The max speed is checked for 24MHz even though she recently stated "SPI is a high speed, 3-wire protocol that can be clocked at up to 12MHz on the ATSAMD21".

The speed is incorrectly calculated. It should be a speed less than or equal to the requested speed. Instead the speed is higher unless the requested speed exactly divides 24 MHz. so if you request 13 MHz you will get 24 MHz , the next SAMD divisor.

If you request a speed less than 95 KHz you will get some random speed up to 24MHz.

[adamgarbo]

Thanks for the insights, Bill (@greiman).

I've used the Adafruit M0 Adalogger for a number of years now and have tended to err on the side of caution by using SD_SCK_MHZ(4). Interesting to know the reasons why the higher speeds don't (currently) work.

Cheers, Adam

[eugeniop]

FWIW, I had to change configuration to 12Mhz on an Adafruit Feather M0 using an external SD card board (a dual SD / e-Ink board).

[jjdeprisco]

I am seeing an SDFat issue with an Emotibit sketch that appears to be related to this issue.

Here's what I am seeing on serial monitor as of today:

I2C data pin: 11 I2C clk pin: 13 hibernate pin: 6 chip sel pin: 19 Firmware version: 1.5.4 firmware_variant: charlieplex_heartbeatOnSleeveJD vregEnablePinLogic: Active HIGH(V3+) EmotiBit not ready. Please check if Battery and SD-Card are present on the EmotiBit. Setup failed: SD-Card not detected

I am also using a Feather M0 WiFi. Can someone tell me exactly where you made the SD_SCK_MHZ change noted above? Which section in which library file? Having trouble locating it. I want to see if this solves my issue.

[greiman]

Use the Adafruit fork of SdFat and contact Adafruit for help.

[jjdeprisco]

Thanks for the quick reply. I've switched over to the Adafruit fork. Seeing same issue, but will f/u with them to see what they suggest.

[greiman]

Let me know what they say. Adafruit software is in a poor state. They now have about 1,600 repositories and not enough staff.

[jjdeprisco]

FWIW, I had to change configuration to 12Mhz on an Adafruit Feather M0 using an external SD card board (a dual SD / e-Ink board).

Where specifically did you make this change?

[adamgarbo]

@jjdeprisco There are plenty of examples of how to configure the microSD card in Bill's library.

If you're looking for something simple, I've used the following line of code to initialize the microSD card on the Feather M0 Adalogger for a number of years:

if (!sd.begin(PIN_MICROSD_CS, SD_SCK_MHZ(4)))
{
    Serial.println("Warning - microSD failed to initialize.");
}

I've found 4 MHz to be reliable. Haven't bothered trying 12 MHz.

Cheers, Adam

[jjdeprisco]

Thanks. I got to the bottom of things. I ended up going almost back to the very beginning, manually removing all of the libraries that were installed for my project , and then reinstalled again. It appears one can not trust the Arduino library manager to fall back on versions for a few things, so I ended up with a few multiple versions in place. Once that was resolved, I managed to get the basic sketch working.

[johnmsole]

Thanks everyone. I battled with adafruit feather M0 adalogger for EXACTLY the same isue. added SD_SCK_MHZ(12) and problem resolved. Wahooo