ALFAT-SC-340 GHI Electronics, ALFAT-SC-340 Datasheet - Page 16

• Manufacturer Part Number: ALFAT-SC-340
• Description: Processors - Application Specialized FILE SYSTEM SoC with DUAL USB HOST & SD
• Manufacturer: GHI Electronics
• Type: File Systemsr

Specifications of ALFAT-SC-340

• Rohs: yes
• Core: ARM Cortex M3
• Processor Series: ALFAT
• Data Bus Width: 32 bit
• Maximum Clock Frequency: 24 MHz
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: LQFP-64
• Interface Type: I2C, SPI, UART
• Part # Aliases: GHI-ALFAT-SC-340

GHI Electronics
Rev. 1.13
SPI DMA receive channel
SPI Bus Configurations
That actual Payload size is calculated as the following: If the requested transaction size
N is larger than ACT then P should equal ACT otherwise P should equal N.
Important: ACT size should be used only for data size estimating purposes because
the send buffer might get filled with more data while processing the read command.
This internal DMA channel that is used for high speed data receiving through SPI bus.
ALFAT opens this DMA channel only when it accepts to receive data with Fast Write to
File command
ALFAT reserves 8192 Bytes in RAM for this DMA channel. So the user can send
8192(or less)-Byte blocks of data without any delays in between the bytes and the DMA
forwards the data to the reserved RAM region. Then ALFAT will save the data into the
file. But the user needs to check SPI_BUSY pin before sending each block.
Check Fast Write to File command
SPI DMA channel. Also ALFAT access reference code library provides an example how
to use L command and access SPI DMA.
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Response
to frame
Ignore
The maximum SPI clock is 24MHz.
SPI clock Idle state is Low.
Sampling is at the rising edge.
SPI_BUSY active state is High.
Data is sent MSB first.
SPI_SSEL active state is Low. SPI_SSEL can be toggled with with every byte or
with every chunk of bytes.
A minimum of 4uS delay is required between each byte. This requirement is not
needed with Fast Write to File command
channel.
type
Internal buffer filled
ACT LSB ACT MSB
(L
16-bit Size ACT
Command).
portion
(L
Page 16 of 51
Command) for more details about how to utilize
Byte 1
if N > ACT then P = ACT else P =N
(L
Payload Bytes, the size is P
Command) that uses
Byte 2
ALFAT access interface
ALFAT SoC Processor
...
www.ghielectronics.com
SPI DMA receive
Byte P