FTDI LibFT4222 User manual

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damages, claims, suits or expense resulting from such use.
Future Technology Devices International Limited (FTDI)
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Tel.: [phone] Fax: + 44 (0) 141 429 2758
Web Site: http://ftdichip.com
Copyright © Future Technology Devices International Limited
Application Note
AN_329
User Guide for LibFT4222
Version 1.5
Issue Date: 2020-04-15
The application note is a guide for LibFT4222 based on D2XX. It provides
high-level and convenient APIs for FT4222H application development.

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AN_329 User Guide For LibFT4222
Version 1.5
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Table of Contents
1Introduction .............................................................. 4
1.1 Overview .............................................................................5
1.2 Scope ..................................................................................7
2Getting Started .......................................................... 8
3Application Programming Interface (API) ............... 10
3.1 Typedefs............................................................................10
3.2 FT4222 General Functions .................................................10
3.2.1 Open and Close ................................................................................ 10
3.2.2 Un-initialize...................................................................................... 10
3.2.3 Set Clock ......................................................................................... 11
3.2.4 Get Clock ......................................................................................... 12
3.2.5 Set Suspend Out............................................................................... 13
3.2.6 Set Wake Up/Interrupt ...................................................................... 14
3.2.7 Set Interrupt Trigger Condition........................................................... 15
3.2.8 Get Max Transfer Size ....................................................................... 18
3.2.9 Set Event Notification ........................................................................ 19
3.2.10 Get Version ...................................................................................... 20
3.2.11 Chip Reset ....................................................................................... 22
3.3 SPI Master Functions ........................................................22
3.3.1 SPI Master Init ................................................................................. 23
3.3.2 SPI Master Set Lines ......................................................................... 25
3.3.3 SPI Master Single Read...................................................................... 26
3.3.4 SPI Master Single Write ..................................................................... 27
3.3.5 SPI Master Single Read and Write ....................................................... 28
3.3.6 SPI Master Multi Read and Write ......................................................... 31
3.4 SPI Slave Functions...........................................................33
3.4.1 SPI Slave Init ................................................................................... 36
3.4.2 SPI Slave Init extend function ............................................................ 37
3.4.3 SPI Slave Set mode function .............................................................. 38
3.4.4 SPI Slave Get Rx Status .................................................................... 39

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3.4.5 SPI Slave Read ................................................................................. 39
3.4.6 SPI Slave Write ................................................................................ 41
3.4.7 SPI Slave RX Response Time .............................................................. 42
3.5 SPI General Functions .......................................................43
3.5.1 SPI Reset Transaction........................................................................ 43
3.5.2 SPI Reset......................................................................................... 44
3.5.3 SPI Set Driving Strength.................................................................... 45
3.6 I2C Master Functions .........................................................46
3.6.1 I2C Master Init ................................................................................. 46
3.6.2 I2C Master Read................................................................................ 47
3.6.3 I2C Master Write .............................................................................. 48
3.6.4 I2C Master Write Extension................................................................. 50
3.6.5 I2C Master Read Extension ................................................................. 51
3.6.6 I2C Master GetStatus......................................................................... 53
3.6.7 I2C Master Reset .............................................................................. 54
3.7 I2C Slave Functions ...........................................................54
3.7.1 I2C Slave Init................................................................................... 54
3.7.2 I2C Slave Get Address ...................................................................... 55
3.7.3 I2C Slave Set Address........................................................................ 56
3.7.4 I2C Slave Get Rx Status ..................................................................... 57
3.7.5 I2C Slave Read ................................................................................. 59
3.7.6 I2C Slave Write ................................................................................. 59
3.7.7 I2C Slave Reset................................................................................. 60
3.7.8 I2C Slave Clock Stretch ...................................................................... 62
3.7.9 I2C Slave Set Response Word ............................................................. 62
3.8 GPIO Functions .................................................................63
3.8.1 GPIO Init ......................................................................................... 63
3.8.2 GPIO Read ....................................................................................... 64
3.8.3 GPIO Write....................................................................................... 65
3.8.4 GPIO Set Input Trigger ...................................................................... 66
3.8.5 GPIO Get Trigger Status .................................................................... 67
3.8.6 GPIO Read Trigger Queue .................................................................. 68
3.8.7 GPIO Set WaveForm Mode ................................................................. 70

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4Contact Information ................................................ 71
Appendix A –Enumeration and Structure Definitions .. 72
Appendix B –References ............................................. 74
Document References ...............................................................74
Acronyms and Abbreviations.....................................................74
Appendix C –List of Tables & Figures .......................... 75
List of Tables.............................................................................75
List of Figures ...........................................................................75
Appendix D –D2XX API support .................................. 76
D2XX supported API .................................................................76
1. FT_CreateDeviceInfoList .......................................................................... 76
Appendix E –Revision History ..................................... 77

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1Introduction
The FT4222H is a USB interface device which supports SPI and I2C communication protocol. It is
accompanied with the support library “LibFT4222”based on D2XX, which provides high-level APIs
to facilitate user application development. At the time of writing support for Windows and Linux OS
has been published. Android support uses a different package also available from the FTDI website.
The FT4222H contains SPI/I2C configurable interfaces. The SPI interface can be configured as
master mode with single, dual, quad bits wide data transfer or slave mode with single bit wide
data transfer. The I2C interface can be configured as master or slave mode.
Figure 1.1 The Software Stack
Note that the Window, Linux and MAC OS version of LibFT4222 have D2XX and mini-boost built-in.
The LibFT4222 sample code, release notes, and all necessary files can be downloaded from the
FTDI website at: https://www.ftdichip.com/Products/ICs/FT4222H.html
The sample source code contained in this application note is provided as an example and is neither
guaranteed nor supported by FTDI.
User Application
LibFT4222
(SPI/I2C Library)
D2XX API
USB Bus driver
FTDI FT4222H chip

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1.1 Overview
The FT4222H supports 4 operation modes to allow various I2C/SPI devices to be connected to USB
bus. The attachable device configuration for each mode is listed below:
Mode 0 (2 USB interfaces):
1 SPI master, SPI slave, I2C master, or I2C slave device
1 GPIO device
Mode 1 (4 USB interfaces):
SPI master connects up to 3 SPI slave devices
1 GPIO device
Mode 2 (4 USB interfaces):
SPI master connects up to 4 SPI slave devices
Mode 3 (1 USB interface):
1 SPI master, SPI slave, I2C master, or I2C slave device
In mode 0 and 3, the connected device can be a SPI/I2C master or slave, depending on how an
application developer initializes the FT4222H chip. Mode 1 and mode 2 are designed to connect to
multiple SPI slave devices.
The FT4222H can be configured with up to 4 GPIO pins for user applications in mode 0 and mode 1,
but each pin is multiplexed with interrupt/suspend out/SPI slave select/I2C functions as listed
below:
gpio0 / ss1o / scl
gpio1 / ss2o / sda
gpio2 / ss3o / suspend out
gpio3 / wakeup/intr
If the FT4222H is initialized as an I2C device, with pins as shown above, the pins of gpio0 and
gpio1 will be switched to scl and sda, and cannot be used as GPIO.
By default the pin for gpio2 is configured as suspend out, and the pin for gpio3 is configured as
wakeup/intr. Only those configured GPIO pins can support GPIO read/set operation through the
corresponding endpoint.
The following diagrams show the examples of FT4222H SPI/I2C master connections.

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Figure 1.2 Mode 0: FT4222H works as SPI master (Quad Mode)
Figure 1.3 Mode 0: FT4222H works as I2C Master

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Figure 1.4 Mode 2: FT4222H works as SPI Master
1.2 Scope
The guide is intended for developers who are creating applications, extending FTDI provided
applications or implementing FTDI’s applications for the FT4222H.

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2Getting Started
A LibFT4222 application usually starts with FT_CreateDeviceInfoList and FT_GetDeviceInfoList as a
traditional D2XX application does. Under different chip modes, FT_CreateDeviceInfoList reports a
different number of interfaces as shown in the table below.
Mode
Number of
Interfaces
Device Function
0
2
a. The first interface: it can be one of SPI master, SPI slave, I2C master,
or I2C slave device.
b. The second interface: GPIO device.
1
4
a. The first 3 interfaces: SPI master connects up to 3 SPI slaves.
b. The 4th interface: GPIO device.
2
4
a. SPI master connects up to 4 SPI slaves. Please refer figure 1.4.
FT4222H works as SPI master.
3
1
a. it can be one of SPI master, SPI slave, I2C master, or I2C slave device.
Table 2.1 Chip Mode and Device Functions
After opening the device with FT_Open, developers need to initialize the FT4222H device as either
SPI master, SPI slave, I2C master, or I2C slave. Different types of device require different
configurations. For more details, please refer the next chapter.
Following example code shows FT4222H works in SPI master mode.
Example#
include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include <string>
#include "ftd2xx.h"
#include "LibFT4222.h"
std::vector< FT_DEVICE_LIST_INFO_NODE > g_FT4222DevList;
inline std::string DeviceFlagToString(DWORD flags)
{
std::string msg;
msg += (flags & 0x1)? "DEVICE_OPEN" : "DEVICE_CLOSED";
msg += ", ";
msg += (flags & 0x2)? "High-speed USB" : "Full-speed USB";
return msg;
}
void ListFtUsbDevices()
{
DWORD numOfDevices = 0;
FT_STATUS status = FT_CreateDeviceInfoList(&numOfDevices);
for(DWORD iDev=0; iDev<numOfDevices; ++iDev)
{
FT_DEVICE_LIST_INFO_NODE devInfo;
memset(&devInfo, 0, sizeof(devInfo));
status = FT_GetDeviceInfoDetail(iDev,
&devInfo.Flags, &devInfo.Type, &devInfo.ID, &devInfo.LocId,
devInfo.SerialNumber, devInfo.Description, &devInfo.ftHandle);
if (FT_OK == status)

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{
printf("Dev %d:\n", iDev);
printf(" Flags= 0x%x, (%s)\n", devInfo.Flags,
DeviceFlagToString(devInfo.Flags).c_str());
printf(" Type= 0x%x\n", devInfo.Type);
printf(" ID= 0x%x\n", devInfo.ID);
printf(" LocId= 0x%x\n", devInfo.LocId);
printf(" SerialNumber= %s\n", devInfo.SerialNumber);
printf(" Description= %s\n", devInfo.Description);
printf(" ftHandle= 0x%x\n", devInfo.ftHandle);
const std::string desc = devInfo.Description;
if(desc == "FT4222" || desc == "FT4222 A") {
g_FT4222DevList.push_back(devInfo);
}
}
}
}
int main(int argc, char const *argv[])
{
ListFtUsbDevices();
if(g_FT4222DevList.empty()) {
printf("No FT4222 device is found!\n");
return 0;
}
FT_HANDLE ftHandle = NULL;
FT_STATUS ftStatus;
FT4222_STATUS ft4222Status;
ftStatus = FT_OpenEx((PVOID)g_FT4222DevList[0].LocId,
FT_OPEN_BY_LOCATION, &ftHandle);
if (FT_OK != ftStatus) {
printf("Open a FT4222 device failed!\n");
return 0;
}
ft4222Status = FT4222_SPIMaster_Init(ftHandle,
SPI_IO_SINGLE, CLK_DIV_4, CLK_ACTIVE_LOW, CLK_LEADING, 0x01);
if (FT4222_OK != ft4222Status) {
printf("Init FT4222 as SPI master device failed!\n");
return 0;
}
// TODO:
// Start to work as SPI master, and read/write data to an SPI slave
// FT4222_SPIMaster_SingleWrite
// FT4222_SPIMaster_SingleRead
// FT4222_SPIMaster_SingleReadWrite
FT4222_Uninitialize(ftHandle);
FT_Close(ftHandle);
return 0;
}