ALFAT-SC-340 GHI Electronics, ALFAT-SC-340 Datasheet - Page 17

• 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

I2C interface uses three hardware signals:
Transmitting and receiving data to and from ALFAT is preformed through standard I2C
transactions. For transmitting, ALFAT-I2C-address with R/W bit set to zero and then the
payload. The payload then is processed internally exactly the same as UART.
Receiving data from ALFAT is similar. The user starts by transmitting ALFAT-I2C-address
with R/W bit set to 1 followed by reading of one or more payload bytes from the internal
buffer. When reading from ALFAT and no data is available, 0x00 (No Data
Token) is returned. Should ALFAT be reading a file and the file contains 0x00 then ALFAT
will return 0xFF (Half Data Token) followed by 0x00. Also, if the file contains 0xFF then
ALFAT will return 0xFF flowed by another 0xFF. The following table shows the states.
Important: With NDT/HDT being used, the actual data size on a files maybe different than
what is received from ALFAT. For example, If a file has one byte and this byte value is
zero, ALFAT will actually send 2 bytes, a 0xFF followed by 0x00. This is all in the I2C
interface driver layer, not in actual communication stream (commands, data) to ALFAT.
This code demonstrates the receive function
4.4. I2C Interface Mode
GHI Electronics
Rev. 1.13
I2C Bus Configuration
ALFAT I2C slave address is 0xA4. This is a fixed address and can't be changed. Bit
zero is the RW bit, 0=Write 1= Read.
The maximum allowed I2C clock is 400Khz. The hosting system must provide pull up
resistors, usually they are 2.2K, on the bus as specified in the I2C specifications.
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UINT8 I2C_GetDataFromALFAT()
{
I2C_SCL: I2C clock signal.
I2C_SDA: I2C data signal.
I2C_BUSY: This should be monitored while sending data to ALFAT. When it is high,
no data should be exchanged with ALFAT.
0x00
0xFF
0x01 … 0xFE
Actual Data coming from File
UINT8 b;
do// wait for data. 0x00 = no data
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0xFF followed by 0x00
0xFF followed by another 0xFF
Data is sent as is
Data transmitted from ALFAT I2C bus
ALFAT access interface
ALFAT SoC Processor
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