ALFAT-OM-337 GHI Electronics, ALFAT-OM-337 Datasheet - Page 28

• Manufacturer Part Number: ALFAT-OM-337
• Description: Memory IC Development Tools ALFAT USB / SD to UART / SPI OEM BOARD
• Manufacturer: GHI Electronics

Specifications of ALFAT-OM-337

• Rohs: yes
• Product: SD OEM Board
• Tool Is For Evaluation Of: SD, SDHC, MMC Cards, USB drives
• Memory Type: Flash
• Operating Supply Voltage: 3.3 V
• Description/function: OEM board offers a seamless way to access files on SD & MMC cards and on USB memory drives
• Interface Type: I2C, SPI, UART, USB
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Part # Aliases: GHI-ALFAT-OM-337

GHI Electronics
Rev. 1.13
R - Read from File
This command is called to read data through a file handle assigned to an open file with
read mode. The user determines the size of data to be read and the filler byte in the
command parameters.
After executing the command, ALFAT sends back the data and increments the internal
file pointer. If the the file pointer reached the end of the file, then ALFAT returns filler
bytes till it reaches the total size required in the R command, then it returns the actual
data size.
Note: the data is sent directly to the user with no formatting (no interpretation or
conversion) in UART and SPI mode. In I2C mode, some of the bytes might be replaced
by two bytes. Check I2C interfaces sections for more details.
Format
Example We have a file with 8 bytes (ABCDEFGH) in it and it is opened for
R
!00
ssssssss Bytes are
returned
$aaaaaaaa
!00
read with handle number 2.
R
!00
ABCDE$00000005
!00
R
!00
FGH^^$00000003
!00
<SP>
<SP>
<SP>
<LF>
<LF>
<LF>
<LF>
<LF>
<LF>
nM>ssssssss
2^>5
2Z>5
<LF>
<LF>
<LF>
<LF>
<LF>
<LF>
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n File Handle 0, 1, 2,3,4,5,6, 7, 8, 9, A, B,
C, D, E or F.
M Filler Character
ssssssss 4 bytes Max. in HEX data size
to read
aaaaaaaa 4 bytes always in HEX actual
read size
Read 5 bytes from file handle 2 with a
filler ^
5 bytes are read
Read 5 more bytes.
Only 3 bytes are available and 2 are filler
bytes
ALFAT SoC Processor
ALFAT Command Set
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