C232HM-DDHSL-0

Application Note AN_178 User Guide For libMPSSE - SPI Document Reference No.: FT_00492 Version 1.1 Issue Date: 2012-02-13 This application note is a guide to using the libMPSSE-SPI – a library which simplifies the design of firmware for interfacing to the FTDI MPSSE configured as an SPI interface. The library is available for Windows and for Linux. Use of FTDI devices in life support and/or safety applications is entirely at the user’s risk, and the user agrees to defend, indemnify and hold harmless FTDI from any and all damages, claims, suits or expense resulting from such use. Future Technology Devices International Limited (FTDI) Unit 1, 2 Seaward Place, Glasgow G41 1HH, United Kingdom Tel.: +44 (0) 141 429 2777 Fax: + 44 (0) 141 429 2758 Web Site: http://ftdichip.com Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 Table of Contents 1 Introduction .................................................................................................................................... 3 2 System Overview............................................................................................................................. 5 3 Application Programming Interface (API) ....................................................................................... 6 3.1 SPI Functions ........................................................................................................................... 6 3.1.1 SPI_GetNumChannels ..................................................................................................... 6 3.1.2 SPI_GetChannelInfo ........................................................................................................ 6 3.1.3 SPI_OpenChannel............................................................................................................ 7 3.1.4 SPI_InitChannel ............................................................................................................... 7 3.1.5 SPI_CloseChannel ............................................................................................................ 8 3.1.6 SPI_Read ......................................................................................................................... 8 3.1.7 SPI_Write ........................................................................................................................ 9 3.1.8 SPI_ReadWrite ................................................................................................................ 9 3.1.9 SPI_IsBusy ..................................................................................................................... 10 3.1.10 SPI_ChangeCS................................................................................................................ 11 3.2 GPIO functions ...................................................................................................................... 11 3.2.1 FT_WriteGPIO ............................................................................................................... 11 3.2.2 FT_ReadGPIO ................................................................................................................ 12 3.3 Library Infrastructure Functions ........................................................................................... 12 3.3.1 Init_libMPSSE ................................................................................................................ 12 3.3.2 Cleanup_libMPSSE ........................................................................................................ 12 3.4 Data types ............................................................................................................................. 13 3.4.1 ChannelConfig ............................................................................................................... 13 3.4.2 Typedefs ........................................................................................................................ 15 4 Example Circuit ............................................................................................................................. 16 5 Example Program .......................................................................................................................... 17 6 Contact Information...................................................................................................................... 24 Appendix A – References ...................................................................................................................... 25 Document References....................................................................................................................... 25 Acronyms and Abbreviations ............................................................................................................ 25 1 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 Appendix C – Revision History .............................................................................................................. 26 2 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 1 Introduction The Multi Protocol Synchronous Serial Engine (MPSSE) is a generic hardware found in several FTDI chips that allows these chips to communicate with a synchronous serial device such an I2C device, a SPI device or a JTAG device. The MPSSE is currently available on the FT2232D, FT2232H, FT4232H and FT232H chips, which communicate with a PC (or an application processor) over the USB interface. Applications on a PC or on an embedded system communicate with the MPSSE in these chips using the D2XX USB drivers. The MPSSE takes different commands to send out data from the chips in the different formats, namely I2C, SPI and JTAG. libMPSSE is a library that provides a user friendly API that enables users to write applications to communicate with the I2C/SPI/JTAG devices without needing to understand the MPSSE and its commands. However, if the user wishes then he/she may try to understand the working of the MPSSE and use it from their applications directly by calling D2XX functions. User Application libMPSSE (SPI/I2C/JTAG Library) D2XX API USB Bus driver FTDI USB-to-Legacy bridge chips Legacy protocol slave device Figure 1: The software and hardware stack through which legacy protocol data flows 3 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 As shown in the above figure, libMPSSE has three different APIs, one each for I2C, SPI and JTAG. This document will only describe the SPI section. The libMPSSE (Linux and Windows versions) sample code, release notes and all necessary files can be downloaded from the FTDI website at : http://www.ftdichip.com/Support/SoftwareExamples/MPSSE.htm The sample source code contained in this application note is provided as an example and is neither guaranteed nor supported by FTDI. 4 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 2 System Overview PC/Host FTDI Chip SPI Device Application SPI Bus SCLK MOSI libMPSSE – SPI MISO USB CS D2XX Driver Figure 2: System organization The above figure shows how the components of the system will typically be organized. The PC/Host may be desktop/laptop machine or an embedded system. The FTDI chip and the SPI device would usually be on the same PCB. Though only one SPI device is shown in the figure above, up to five SPI devices can actually be connected to each MPSSE. 5 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 3 Application Programming Interface (API) The libMPSSE-SPI APIs can be divided into two broad sets. The first set consists of six control APIs and the second set consists of two data transferring APIs. All the APIs return an FT_STATUS. This is the same FT_STATUS that is defined in the D2XX driver. 3.1 SPI Functions 3.1.1 SPI_GetNumChannels FT_STATUS SPI_GetNumChannels (uint32 *numChannels) This function gets the number of SPI channels that are connected to the host system. The number of ports available in each of these chips is different. Parameters: out *numChannels The number of channels connected to the host Returns: Returns status code of type FT_STATUS Note: FTDI’s USB-to-legacy bridge chips may have multiple channels in it but not all these channels can be configured to work as SPI masters. This function returns the total number of channels connected to the host system that has a MPSSE attached to it so that it may be configured as an SPI master. For example, if an FT2232D (1 MPSSE port), an FT232H (1 MPSSE port), an FT2232H (2 MPSSE ports) and an FT4232H (2 MPSSE ports) are connected to a PC, then a call to SPI_GetNumChannels would return 6 in numChannels. Warning: This function should not be called from two applications or from two threads at the same time. 3.1.2 SPI_GetChannelInfo FT_STATUS SPI_GetChannelInfo (uint32 index, FT_DEVICE_LIST_INFO_NODE *chanInfo) This function takes a channel index (valid values are from 0 to the value returned by SPI_GetNumChannels - 1) and provides information about the channel in the form of a populated FT_DEVICE_LIST_INFO_NODE structure. Parameters: in index Index of the channel out *chanInfo Pointer to FT_DEVICE_LIST_INFO_NODE structure Returns: Returns status code of type FT_STATUS 6 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 Note: This API could be called only after calling SPI_GetNumChannels. See also: Structure definition of FT_DEVICE_LIST_INFO_NODE is in the D2XX Programmer's Guide. Warning: the 3.1.3 This function should not be called from two applications or from two threads at same time. SPI_OpenChannel FT_STATUS SPI_OpenChannel (uint32 index, FT_HANDLE *handle) This function opens the indexed channel and provides a handle to it. Valid values for the index of channel can be from 0 to the value obtained using SPI_GetNumChannels - 1). Parameters: in index Index of the channel out handle Pointer to the handle of type FT_HANDLE Returns: Returns status code of type FT_STATUS Note: Trying to open an already open channel will return an error code. 3.1.4 SPI_InitChannel FT_STATUS SPI_InitChannel (FT_HANDLE handle, ChannelConfig *config) This function initializes the channel and the communication parameters associated with it. Parameters: in handle Handle of the channel in config Pointer to ChannelConfig structure with the value of clock and latency timer updated Returns: Returns status code of type FT_STATUS See also: Structure definition of ChannelConfig Note: This function internally performs what is required to get the channel operational such as resetting and enabling the MPSSE. 7 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 3.1.5 Clearance No.: FTDI# 215 SPI_CloseChannel FT_STATUS SPI_CloseChannel (FT_HANDLE handle) Closes a channel and frees all resources that were used by it Parameters: in handle out none Handle of the channel Returns: Returns status code of type FT_STATUS 3.1.6 SPI_Read FT_STATUS SPI_Read(FT_HANDLE handle, uint8 *buffer, uint32 sizeToTransfer, uint32 *sizeTransferred, uint32 transferOptions) This function reads the specified number of bits or bytes (depending on transferOptions parameter) from an SPI slave. Parameters: in handle Handle of the channel out buffer Pointer to the buffer where data is to be read in sizeToTransfer Number of bytes or bits to be read out *sizeTransferred Pointer to variable containing the number of bytes or bits read in transferOptions This parameter specifies data transfer options. The bit positions defined for each of these options are: BIT0: if set then sizeToTransfer is in bits, otherwise bytes. Bit masks defined for this bit are SPI_TRANSFER_OPTIONS_SIZE_IN_BYTES and SPI_TRANSFER_OPTIONS_SIZE_IN_BITS BIT1: if set then the chip select line is asserted before beginning the transfer. Bit mask defined for this bit is SPI_TRANSFER_OPTIONS_CHIPSELECT_ENABLE BIT2: if set then the chip select line is disserted after the transfer ends. Bit mask defined for this bit is SPI_TRANSFER_OPTIONS_CHIPSELECT_DISABLE BIT3 – BIT31: reserved Returns: Returns status code of type FT_STATUS 8 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 Warning: This is a blocking function and will not return until either the specified amounts of data are read or an error is encountered. 3.1.7 SPI_Write FT_STATUS SPI_ Write(FT_HANDLE handle, uint8 *buffer, uint32 sizeToTransfer, uint32 *sizeTransferred, uint32 transferOptions) This function writes the specified number of bits or bytes (depending on transferOptions parameter) to a SPI slave. Parameters: in handle Handle of the channel out buffer Pointer to the buffer from where data is to be written in sizeToTransfer Number of bytes or bits to write out *sizeTransferred Pointer to variable containing the number of bytes or bits written in transferOptions This parameter specifies data transfer options. The bit positions defined for each of these options are: BIT0: if set then sizeToTransfer is in bits, otherwise bytes. Bit masks defined for this bit are SPI_TRANSFER_OPTIONS_SIZE_IN_BYTES and SPI_TRANSFER_OPTIONS_SIZE_IN_BITS BIT1: if set then the chip select line is asserted before beginning the transfer. Bit mask defined for this bit is SPI_TRANSFER_OPTIONS_CHIPSELECT_ENABLE BIT2: if set then the chip select line is disserted after the transfer ends. Bit mask defined for this bit is SPI_TRANSFER_OPTIONS_CHIPSELECT_DISABLE BIT3 – BIT31: reserved Returns: Returns status code of type FT_STATUS Warning: This is a blocking function and will not return until either the specified amount of data is read or an error is encountered. 3.1.8 SPI_ReadWrite FT_STATUS SPI_ReadWrite(FT_HANDLE handle, uint8 *inBuffer, uint8 *outBuffer, uint32 sizeToTransfer, uint32 *sizeTransferred, uint32 transferOptions) This function reads from and writes to the SPI slave simultaneously. Meaning that, one bit is clocked in and one bit is clocked out during every clock cycle. 9 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 Parameters: in handle Handle of the channel in *inBuffer Pointer to buffer to which data read will be stored out outBuffer Pointer to the buffer from where data is to be written in sizeToTransfer Number of bytes or bits to write out *sizeTransferred Pointer to variable containing the number of bytes or bits written in transferOptions This parameter specifies data transfer options. The bit positions defined for each of these options are: BIT0: if set then sizeToTransfer is in bits, otherwise bytes. Bit masks defined for this bit are SPI_TRANSFER_OPTIONS_SIZE_IN_BYTES and SPI_TRANSFER_OPTIONS_SIZE_IN_BITS BIT1: if set then the chip select line is asserted before beginning the transfer. Bit mask defined for this bit is SPI_TRANSFER_OPTIONS_CHIPSELECT_ENABL E BIT2: if set then the chip select line is disserted after the transfer ends. Bit mask defined for this bit is SPI_TRANSFER_OPTIONS_CHIPSELECT_DISAB LE BIT3 – BIT31: reserved Returns: Returns status code of type FT_STATUS Warning: This is a blocking function and will not return until either the specified amount of data is transferred or an error is encountered. 3.1.9 SPI_IsBusy FT_STATUS SPI_ IsBusy(FT_HANDLE handle, bool *state) This function reads the state of the MISO line without clocking the SPI bus. Some applications need the SPI master to poll the MISO line without clocking the bus to check if the SPI slave has completed previous operation and is ready for the next operation. This function is useful for such applications. Parameters: in handle Handle of the channel out *state Pointer to a variable to which the state of the MISO 10 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 line will be read Returns: Returns status code of type FT_STATUS 3.1.10 SPI_ChangeCS FT_STATUS SPI_ChangeCS(FT_HANDLE handle, uint32 configOptions) This function changes the chip select line that is to be used to communicate to the SPI slave. Parameters: in handle Handle of the channel in configOptions This parameter provides a way to select the chip select line and the slave's SPI mode. It is the same parameter as ConfigChannel.configOptions that is passed to function SPI_InitChannel and it is explained in section 3.4.1 Returns: Returns status code of type FT_STATUS 3.2 GPIO functions Each MPSSE channel in the FTDI chips are provided with a general purpose I/O port having 8 lines in addition to the port that is used for synchronous serial communication. For example, the FT232H has only one MPSSE channel with two 8-bit ports, ADBUS and ACBUS. Out of these, ADBUS is used for synchronous serial communications (I2C/SPI/JTAG) and ACBUS is free to be used as GPIO. The two functions described below have been provided to access these GPIO lines (also called the higher byte lines of MPSSE) that are available in various FTDI chips with MPSSEs. 3.2.1 FT_WriteGPIO FT_STATUS FT_WriteGPIO(FT_HANDLE handle, uint8 dir, uint8 value) This function writes to the 8 GPIO lines associated with the high byte of the MPSSE channel Parameters: in handle Handle of the channel in dir Each bit of this byte represents the direction of the 8 respective GPIO lines. 0 for in and 1 for out in value If the direction of a GPIO line is set to output, then each bit of this byte represent the output logic state of the 8 respective GPIO lines. 0 for logic low and 1 for logic high Returns: Returns status code of type FT_STATUS 11 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 3.2.2 Clearance No.: FTDI# 215 FT_ReadGPIO FT_STATUS FT_ReadGPIO(FT_HANDLE handle, uint8 *value) This function reads from the 8 GPIO lines associated with the high byte of the MPSSE channel Parameters: in handle Handle of the channel out *value If the direction of a GPIO line is set to input, then each bit of this byte represent the input logic state of the 8 respective GPIO lines. 0 for logic low and 1 for logic high Returns: Returns status code of type FT_STATUS Note: The direction of the GPIO line must first be set using FT_WriteGPIO function before this function is used. 3.3 Library Infrastructure Functions The two functions described in this section typically do not need to be called from the user applications as they are automatically called during entry/exit time. However, these functions are not called automatically when linking the library statically using Microsoft Visual C++. It is then that they need to be called explicitly from the user applications. The static linking sample provided with this manual uses a macro which checks if the code is compiled using Microsoft toolchain, if so then it automatically calls these functions. 3.3.1 Init_libMPSSE void Init_libMPSSE(void) Initializes the library Parameters: in none out none Returns: void 3.3.2 Cleanup_libMPSSE void Cleanup_libMPSSE(void) 12 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 Cleans up resources used by the library Parameters: in none out none Returns: void 3.4 Data types 3.4.1 ChannelConfig ChannelConfig is a structure that holds the parameters used for initializing a channel. The following are members of the structure: uint32 ClockRate This parameter takes the value of the clock rate of the SPI bus in hertz. Valid range for ClockRate is 0 to 30MHz. uint8 LatencyTimer Required value, in milliseconds, of latency timer. Valid range is 0 – 255. However, FTDI recommend the following ranges of values for the latency timer: Range for full speed devices (FT2232D): Range 2 – 255 Range for Hi-speed devices (FT232H, FT2232H, FT4232H): Range 1 - 255 uint32 configOptions Bits of this member are used in the way described below: Bit number Description Valu e Meaning of value Defined macro(if any) BIT1BIT0 These bits specify to which of the standard SPI modes should the SPI master be configured to 00 SPI MODE0 SPI_CONFIG_OPTION_MODE0 01 SPI MODE1 SPI_CONFIG_OPTION_MODE1 ( Please refer to the release notes within the release package zip file for revision history and known limitations of this version) 10 SPI MODE2 SPI_CONFIG_OPTION_MODE2 11 SPI MODE3 SPI_CONFIG_OPTION_MODE3 (Please refer to the release notes within the release package zip file for revision history and known limitations of this version) BIT4BIT2 These bits specify which of the available lines should be used as chip 000 xDBUS3 of MPSSE is chip select SPI_CONFIG_OPTION_CS_DBUS3 001 xDBUS4 of MPSSE is SPI_CONFIG_OPTION_CS_DBUS4 13 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 select BIT5 BIT6BIT31 This bit specifies if the chip select line should be active low Clearance No.: FTDI# 215 chip select 010 xDBUS5 of MPSSE is chip select SPI_CONFIG_OPTION_CS_DBUS5 011 xDBUS6 of MPSSE is chip select SPI_CONFIG_OPTION_CS_DBUS6 100 xDBUS7 of MPSSE is chip select SPI_CONFIG_OPTION_CS_DBUS7 0 Chip select is active high 1 Chip select is active low SPI_CONFIG_OPTION_CS_ACTIVELOW Reserved Note: The terms xDBUS0 – xDBUS7 corresponds to lines ADBUS0 – ADBUS7 if the first MPSSE channel is used, otherwise it corresponds to lines BDBUS0 – BDBUS7 if the second MPSSE channel(i.e. if available in the chip) is used. The SPI modes are: SPI MODE0 - data are captured on rising edge and propagated on falling edge SPI MODE1 - data are captured on falling edge and propagated on rising edge SPI MODE2 - data are captured on falling edge and propagated on rising edge SPI MODE3 - data are captured on rising edge and propagated on falling edge uint32 Pins This member specifies the directions and values of the lines associated with the lower byte of the MPSSE channel after SPI_InitChannel and SPI_CloseChannel functions are called. Bit number Description Comment BIT7-BIT0 Direction of the lines after A 1 corresponds to output and a 0 corresponds to input SPI_InitChannel is called BIT15-BIT8 Value of the lines after SPI_InitChannel is called BIT23-BIT16 Direction of the lines after SPI_CloseChannel is called BIT31-BIT24 Value of the lines after SPI_CloseChannel is called A 1 corresponds to logic high and a 0 corresponds to logic low A 1 corresponds to output and a 0 corresponds to input A 1 corresponds to logic high and a 0 corresponds to logic low Note that the directions of the SCLK, MOSI and the specified chip select line will be overwritten to 1 and the direction of the MISO like will be overwritten to 0 14 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 irrespective of the values passed by the user application. Other than these 4 lines, the rest of the lines will be an a state that is specified via this parameter. uint16 reserved This parameter is reserved and should not be used. 3.4.2 Typedefs Following are the typedefs that have been defined keeping cross platform portability in view: typedef typedef typedef typedef typedef typedef typedef unsigned char uint8 unsigned short uint16 unsigned long uint32 signed char int8 signed short int16 signed long int32 unsigned char bool 15 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 4 Example Circuit This example will demonstrate how to connect a MPSSE chip (FT2232H) to an SPI device (93LC56B – EEPROM) and program it using libMPSSE-SPI library. Figure 3: Schematic for connecting FT2232H to SPI EEPROM device (93LC56B) The above schematic shows how to connect a FT2232H chip to an SPI EEPROM. Please note that the FT2232H chip is also available as a module which contains all the components shown in the above schematic (except the 93LC56B and the pull-up resistors connected to it). This module is called FT2232H Mini Module and details about it can be found in the device datasheet. The FT2232H chip acts as the SPI master here and is connected to a PC running using USB interface. 16 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 Clearance No.: FTDI# 215 5 Example Program The required D2XX driver should be installed into the system depending on the OS that is already installed in the PC/host. If a linux PC is used then the default drivers usbserial and ftdi_sio must be removed (using rmmod command). Once the hardware shown above is connected to a PC and the drivers are installed, we can place the following sample code (sample-static.c), D2XX.h, libMPSSE_spi.h and libMPSSE.a into one folder, compile the sample and run it. /*! * \file sample-static.c * * \author FTDI * \date 20110512 * * Copyright © 2011 Future Technology Devices International Limited * Company Confidential * * Project: libMPSSE * Module: SPI Sample Application - Interfacing 94LC56B SPI EEPROM * * Rivision History: * 0.1 - 20110512 - Initial version * 0.2 - 20110801 - Changed LatencyTimer to 255 * Attempt to open channel only if available * Added & modified macros * Included stdlib.h * 0.3 - 20111212 - Added comments */ /******************************************************************************/ /* Include files */ /******************************************************************************/ /* Standard C libraries */ #include #include /* OS specific libraries */ #ifdef _WIN32 #include #endif /* Include D2XX header*/ #include "ftd2xx.h" /* Include libMPSSE header */ #include "libMPSSE_spi.h" /******************************************************************************/ /* Macro and type defines */ /******************************************************************************/ /* Helper macros */ #define APP_CHECK_STATUS(exp) {if(exp!=FT_OK){printf("%s:%d:%s(): status(0x%x) \ != FT_OK\n",__FILE__, __LINE__, __FUNCTION__,exp);exit(1);}else{;}}; #define CHECK_NULL(exp){if(exp==NULL){printf("%s:%d:%s(): NULL expression \ encountered \n",__FILE__, __LINE__, __FUNCTION__);exit(1);}else{;}}; /* Application specific macro definations */ #define SPI_DEVICE_BUFFER_SIZE 256 17 Copyright © 2011 Future Technology Devices International Limited Application Note AN_178 Programming Guide for libMPSSE - SPI Version 1.1 Document Reference No.: FT_00492 #define SPI_WRITE_COMPLETION_RETRY #define START_ADDRESS_EEPROM #define END_ADDRESS_EEPROM #define RETRY_COUNT_EEPROM #define CHANNEL_TO_OPEN #define SPI_SLAVE_0 #define SPI_SLAVE_1 #define SPI_SLAVE_2 #define DATA_OFFSET Clearance No.: FTDI# 215 10 0x00 /*read/write start address inside the EEPROM*/ 0x10 10 /* number of retries if read/write fails */ 0 /*0 for first available channel, 1 for next... */ 0 1 2 3 /******************************************************************************/ /* Global variables */ /******************************************************************************/ uint32 channels; FT_HANDLE ftHandle; ChannelConfig channelConf; uint8 buffer[SPI_DEVICE_BUFFER_SIZE]; /******************************************************************************/ /* Public function definitions */ /******************************************************************************/ /*! * \brief Writes to EEPROM * * This function writes a byte to a specified address within the 93LC56B EEPROM * * \param[in] slaveAddress Address of the I2C slave (EEPROM) * \param[in] registerAddress Address of the memory location inside the slave to where the byte * is to be written * \param[in] data The byte that is to be written * \return Returns status code of type FT_STATUS(see D2XX Programmer's Guide) * \sa Datasheet of 93LC56B http://ww1.microchip.com/downloads/en/DeviceDoc/21794F.pdf * \note * \warning */ FT_STATUS read_byte(uint8 slaveAddress, uint8 address, uint16 *data) { uint32 sizeToTransfer = 0; uint32 sizeTransfered; bool writeComplete=0; uint32 retry=0; bool state; FT_STATUS status; /* CS_High + Write command + Address */ sizeToTransfer=1; sizeTransfered=0; buffer[0] = 0xC0;/* Write command (3bits)*/ buffer[0] = buffer[0] | ( ( address >> 3) & 0x0F );/*5 most significant add bits*/ status = SPI_Write(ftHandle, buffer, sizeToTransfer, &sizeTransfered, SPI_TRANSFER_OPTIONS_SIZE_IN_BYTES| SPI_TRANSFER_OPTIONS_CHIPSELECT_ENABLE); APP_CHECK_STATUS(status); /*Write partial address bits */ sizeToTransfer=4; sizeTransfered=0; buffer[0] = ( address & 0x07 )