FTDI LibFT4222 - SPI Master Multi Read and Write; Figure 3.2 Dual SPI Communications

Application Note
AN_329 User Guide For LibFT4222
Version 1.5
Document Reference No.: FT_001060 Clearance No.: FTDI#406
31
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3.3.6 SPI Master Multi Read and Write
FT4222_STATUS FT4222_SPIMaster_MultiReadWrite(FT_HANDLE ftHandle, uint8* readBuffer,
uint8* writeBuffer, uint8 singleWriteBytes,uint16 multiWriteBytes,uint16 multiReadBytes, uint32*
sizeOfRead)
Supported Chip:
FT4222 chip version
Supported
FT4222 Rev A
YES
FT4222 Rev B
YES
FT4222 Rev C
YES
FT4222 Rev D
YES
Summary:
Under SPI dual or quad mode, write data to and read data from an SPI slave.
The figure below illustrates the dual-SPI protocol supported by the FT4222H SPI master. It is a
mixed protocol initiated with a single write transmission, which may be an SPI command and
dummy cycles, and followed by dual-write and dual-read transmission that use 2 signals in parallel
for the data. All three parts of the protocol are optional. For example, developers can ignore the
multi-read part by setting multiReadBytes=0.
Figure 3.2 Dual SPI communications
The figure below illustrates the quad-SPI protocol supported by the FT4222H SPI master. It is the
same as the dual-protocol illustrated above - it is a mixed protocol initiated with a single write
transmission and followed by quad-write and quad-read transmission that use 4 signals in parallel
for the data.