INSTRUCTION MANUAL PC1 USB TO SPI INTERFACE

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INSTRUCTION MANUAL PC1 USB TO SPI INTERFACE Date 3/3/09 Doc # 9016sm01 Revision 2 AOS TECHNOLOGY LIMITED T. +44 (0)1664 567711 F.

1 INSTRUCTION MANUAL PC1 USB TO SPI INTERFACE Date 3/3/09 Doc # 9016sm01 Revision 2 AOS TECHNOLOGY LIMITED T. +44 (0) F. +44 (0) E. mail@aost.co.uk 46 Pate Rd MELTON MOWBRAY LE13 0RG United Kingdom Registration No VAT No

2 REVISION TABLE Date Revision Description 3/3/09 1 General text changes. 11/01/10 2 J3 pin description corrected Not to be reproduced without permission Page 2 of 18

3 LIST OF CONTENTS INSTRUCTION MANUAL... 1 PC1 USB TO SPI INTERFACE... 1 REVISION TABLE... 2 LIST OF CONTENTS... 3 LIST OF TABLES... 4 LIST OF figures INTRODUCTION FUNCTIONAL DESCRIPTION PIN DESCRIPTIONS CONTROL INTERFACE Data Configuration Data Commands WRITE contents of serial register to RDAC (A0) WRITE contents of serial register to RDAC (A1) SAVE contents of RDAC (A0) to EEMEM (A0) SAVE contents of RDAC (A1) to EEMEM (A1) SOFTWARE CONTROL Users Own Software Comments on User Interfacing AOS APPLICATION SOFTWARE Driver and Software Support Main Program Screen: Single Controller Running the single user application for the first time Running the application software First steps in setting up the interface Temperature Tab Setup Tab Limits Tab File Data Tab Main Program Screen: Multiple Controller Running the Multi interface application for the first time Running the Multi interface application software First steps in setting up the multi interface Using multiple boards...18 Not to be reproduced without permission Page 3 of 18

4 LIST OF TABLES Table 1 16 Bit Serial Data Word... 9 LIST OF figures Figure 1 Schematic of USB functional controls... 6 Figure 2. Photograph of the PC1 controller board... 6 Figure 3. Silkscreen of PC1 controller board... 7 Figure 4. Schematic of the SPI interface bus connections... 9 Figure 5. Main software screen...13 Figure 6. Main software screen-multi controller...16 Not to be reproduced without permission Page 4 of 18

5 1. INTRODUCTION The PC1 USB interface is a small piggyback-mounted printed circuit board (PCB) which has been designed to enable computer control of the AOS Technology Ltd PC1 series peltier controllers. The interface is based around an FTDI supplied DLP2232M dual UART interface module that is configured to run a simple serial peripheral interface (SPI) bus. Connected to this bus in a daisy-chain fashion are four dual channel digital potentiometers. The majority of these controllable pots are used as potential dividers in order to provide suitable control voltages to the PC1 peltier controller board. A spare potentiometer is left unassigned and can be used as either a simple variable resistor or as part of an internal potential divider network. The temperature setpoint on the PC1 is controlled in the manual version using a 13 turn miniature pot, this provides about 11bit of voltage resolution across the control scale. The USB interface board uses a combination of three digital pots in order to provide full 16 bit control of this voltage, a significant improvement over the manual version. Chip ENABLE functions and the ability to set the maximum current, both in a positive (cooling) and negative (heating) direction, as well as the maximum voltage that can be applied across the peltier element can also be controlled using this interface. Once the controller settings have been updated they can then be written/saved to the memory section on each of the digital pot chips. This default memory value is retained even during power down and is the default value loaded when the chips are RESET or powered up. The memory retention period is stated at 100 years and it can be written to over 100 thousand times. Since the FTDI module is a dual channel UART, only one of which is utilised by the SPI interface, connections to the other are provided by a series of on board solder pads. This allows the interface to be used to control the PC1 (or in alternative direct control applications) while providing an additional control interface. It is not the purpose of this document to explore the potential applications or outline the control possibilities of this additional interface any further. AOS TECHNOLOGY LIMITED T. +44 (0) F. +44 (0) E. mail@aost.co.uk 46 Pate Rd MELTON MOWBRAY LE13 0RG United Kingdom Registration No VAT No

1 FUNCTIONAL DESCRIPTION The SPI interface board is usually mounted directly below the PC1 series peltier controller board and interfaces directly via a series of header pins through the bottom of

6 1 FUNCTIONAL DESCRIPTION The SPI interface board is usually mounted directly below the PC1 series peltier controller board and interfaces directly via a series of header pins through the bottom of the PC1 board. Four corner board stand-offs provide additional mechanical support and a means on mounting the controller to a substrate. The schematic below indicates the various PC1 controller board functions that can be controlled via the SPI interface card. Figure 1 Schematic of USB functional controls 2 PIN DESCRIPTIONS Figure 2. Photograph of the PC1 controller board Not to be reproduced without permission Page 6 of 18

7 Figure 3. Silkscreen of PC1 controller board P6 PWR connector Pin Description 1 +Vcc 2 0 volts P5 TEC connector Pin Description 1 TEC + 2 TEC - P4 Interface connector Pin Description 1 Vcc 2 0 volts 3 Bufref 4 Shutdn Not to be reproduced without permission Page 7 of 18

8 J3 interface Jumper Connection Pin Description 1 Vmax set point voltage from potentiometer 2 Vmax set point voltage input to controller 3 Iset(+ve) set point voltage from potentiometer 4 Iset(+ve) set point voltage input to controller 5 Iset(-ve) set point voltage from potentiometer 6 Iset(-ve) set point voltage input to controller 7 Vsetpoint set point voltage from potentiometer 8 Vsetpoint set point voltage input to controller NB for PC1 standalone use, pins 1-2, 3-4, 5-6, 7-8 are bridged For PC1-USB, the pins in this connector MUST NOT BE BRIDGED. The set point voltage inputs to the controller are provided by the USB board J4 External control loop connector Pin Description 1 U3 pin1 2 U3 pin3 3 U4B pin1 J2 Control input connector Pin Description 1 Therm 2 Shutdn 3 Imon 4 0 volts 3 CONTROL INTERFACE As mentioned above the control interface consists of an SPI bus controlling four daisy-chained, dual channel, 8 bit, digital pots. A schematic of the outline system configuration can be seen in the diagram below. Not to be reproduced without permission Page 8 of 18

9 Figure 4. Schematic of the SPI interface bus connections The digital potentiometers must be addressed using either the SPI mode 0 (CPOL=1, CPHA=0) or mode 1 (CPOL=1, CPHA=1) protocols. The LabView demonstration software supplied with this interface has been configured to operate with a mode 0 protocol. Correct mode operation must be ensured for robust interface operation especially if user based software is required. 3.1 Data Configuration Data is written to the interface and clocked through all four chips using an eight byte control string. The write sequence is initiated by driving the chip select pin low and synchronously clocking the data through the chips. Each chip receiving two byte of information when the chip select line is driven high. The 16 bit serial data word which is latched into each chip at the end of the write sequence is formatted and consists of a control nibble, an address nibble and a data byte. Table 1 16 Bit Serial Data Word While the chips are capable of operating in a number of different modes the basic requirement of the interface consist of two functions; Not to be reproduced without permission Page 9 of 18

10 WRITE data to the appropriate RDAC register. Writing data to this register will update the digital pot setting. Each chip has two registers, each which must be written to individually. SAVE data to the appropriate EEMEM location. Initiating a save command will write the data currently held in the RDAC register to the corresponding EEMEM location. The data held at this location is used during power up and reset to configure the digital potentiometers. Each chip has two EEMEM locations, each which must be saved to individually. Since it is only possible to write or save to one of digital pots at a time then two eight byte control strings must be used in order to fully address all the digital pots on the interface. While it is possible to write/save to bank 0 on chip4 followed by bank 1 on chip 3 etc it is much easier if one complete bank is written to at a time. The supplied software operates in this manner, either writing or saving to all the bank 0 RDAC/EEMEM registers/locations followed by all the bank1 RDAC/EEMEM registers/locations. 3.2 Data Commands A full listing of the instruction commands associated with the digital pot chips can be found in the AD5232 data sheet 1. There are only four separate command codes used by this interface to update to the interface (RDAC) and save it to the chip memory (EEMEM) WRITE contents of serial register to RDAC (A0) The Hex command B0XX H is used latch the 8 bit data byte XX into the RDAC register used to control the bank 0 pot position WRITE contents of serial register to RDAC (A1) The Hex command B1XX H is used latch the 8 bit data byte XX into the RDAC register used to control the bank 1 pot position SAVE contents of RDAC (A0) to EEMEM (A0) The Hex command 20xx H is used save the RDAC (A0) data into the EEMEM (A0) memory location. N.B. in this case the contents of the lower byte are unimportant and hence ignored. 1 AD5232, Analog Devices, 8-bit Dual Nonvolatile Memory Digital Potentiometer Not to be reproduced without permission Page 10 of 18

11 3.2.4 SAVE contents of RDAC (A1) to EEMEM (A1) The Hex command 21xx H is used save the RDAC (A1) data into the EEMEM (A1) memory location. N.B. in this case the contents of the lower byte are unimportant and hence ignored. Not to be reproduced without permission Page 11 of 18

12 4 SOFTWARE CONTROL The heart of the USB to SPI interface module is a third generation USB dual UART module manufactured by DLP Design Inc and supplied by FTDI. FTDI provides a royal free Virtual Com Port (VCP) driver that makes the peripheral ports look like a standard COM port to the PC. Most existing software applications should be able to interface with the Virtual Com Port simply by reconfiguring them to use the new ports created by the driver. Using the VCP drivers, an application programmer would communicate with the device in exactly the same way as they would a regular PC COCM port using the Windows API calls or a COM port library. The FT2232C driver also incorporates the functions defined for the FTDI s D2XX drivers, allowing applications programmers to interface software directly to the device using a Windows DLL. While there are a large number of different ways of communicating with this USB UART module it is not the purpose of this document to act as an allencompassing software reference manual. In addition to the VCP and D2XX drivers FTDI provide a series of LabView Vis that can be used to access all the functions of this module. The software control applications provided with this interface use a combination of the more general FT_ series Vis and the more specific SPI_ Vis. Both series of drivers are provided on the CD. 4.1 Users Own Software The FTDI website contains all the driver information and documentation required to produce a custom user interface. In addition the support pages provide information about using the DLL driver with C Comments on User Interfacing Although it is relatively simple process to write a custom user interface utilising the supplied resources it is important that the data sent across the interface is correctly configured. Examination of the chip select, clock and data line on a storage scope will provide a quick insight into the correct operation of the interface. Given that the transfer speed across the interface can be significant it may be prudent to slow the clock rate in order to view the data successfully. Not to be reproduced without permission Page 12 of 18

13 5 AOS APPLICATION SOFTWARE The AOS application software consists of a built LabView application with its own installer. Instruction for installing the software can be found in document 9016sw01 provided in the attached CD. 5.1 Driver and Software Support The D2XX driver used in the development of the LabView application Vis will support the following operating systems. The version used in this development is version available on the Drivers page of the FTDI website. Windows Vista Windows Vista x64 Windows XP Windows XP x64 Windows Main Program Screen: Single Controller Figure 5. Main software screen Not to be reproduced without permission Page 13 of 18

14 This application is designed to control a single SPI interface module connected to an AOS PC1 controller. If more than one SPI interface module is connected to the control PC then this is indicated in the announcement window of the application while the serial number of interface under control is indicated below this, FT04CDDWA, in the above figure. This application control interface consists of a number announcement windows, control buttons and setup tabs Running the single user application for the first time Although the SPI interface controller board is supplied with the TEC current and voltage limits set to zero, the control setpoint voltage set to its mid position and the controller disabled it is a good idea to confirm these setting before connecting the interface to the PC1 controller board. This can be accomplished by leaving the TEC and thermistor unconnected while running the application program. Details about the application controls can be found in the next section Running the application software To start the controller and control application do the following; Connect the PC1 and USB interface boards together Connect all appropriate connections to the PC1 board, PWR, TEC connections and thermistor connections. Connect the USB connector to the USB board and the PC ( N.B. the SPI board obtains power from the PC1 board) Select the PC1 single controller program from the main program menu. It will automatically start. (The board will start up without the controller enabled as this is the saved state of the USB interface before dispatch). If you are unsure or the start up conditions are unknown it would be wise to disable the controller manually by shorting pin 2 to pin 4 on the J2 control input and then setting and updating/saving suitable limits settings to the SPI board before removing the shorting pin and using the application. The main screen consists of a number of control buttons placed vertically along the left hand side of the screen and some setup tabs that contain the setup data for the controller. The Control buttons have the following function; Not to be reproduced without permission Page 14 of 18

15 RESET: sets all control voltages to zero volts and sets the wiper on the spare potentiometer to one end of the scale. UPDATE: The PC1 USB interface is updated with the current settings (those outlined in the set up tabs). These setting are not held after subsequent power up. UPDATE from file: this button updates the PC1 USB interface from data previously saved to file SAVE to file: saves the current setting to file. SAVE to PC1: saves the current settings to the PC1 USB memory. If powered down and then re-energised then the last saved setting will be present on the interface. STOP: Stops the application. The previous setting will be held until power down. At subsequent power up the previously saved settings (not the last updated settings) will be present on the interface First steps in setting up the interface There are a number of controller settings that MUST be implemented before turning on the controller in a real application. In order of importance these are; Set suitable TEC current and voltage limits. Failure to set suitable limits may result in the controller overdriving the TEC element and this may lead to component degradation or failure. Set suitable thermistor beta or Steinhart-Hart coefficients. Setting suitable coefficient will enable accurate temperature indication, within the specifications of the fitting algorithm. Set a suitable temperature setpoint. Enable or Disable the controller Temperature Tab Settings on this tab allow the user to update the temperature and enable the controller. N.B. the enable function is a logical OR with any direct electrical connections, the software control will therefore have no effect if any other electrical connections dictate the pin enable functionality Setup Tab Settings on this tab allow the user to set the thermistor parameters to be used for the temperature sensor. There are two options; Beta parameters and Steinhart Hart parameters. The subtab visible dictate the parameters used. Typically these parameters can be obtained from the thermistor manufacturer or by experimentation. Not to be reproduced without permission Page 15 of 18

16 5.2.6 Limits Tab Settings on this tab allow the user to set the maximum voltage and currents that can be applied across and through the Peltier element. Settings allow for different current limits in both directions through the element. The value of the sense resistor (usually 50 millohms) is set here as is the nominal value of the spare potentiometer. N.B. the absolute value of the spare pot must be confirmed by measurement due to the substantial component value variation. The sense resistor should not be changed as this reflects the hardware value found on the PC1 controller board File Data Tab This indicates the data saved to file. 5.3 Main Program Screen: Multiple Controller Figure 6. Main software screen-multi controller This application is designed to control multiple SPI interface modules connected to AOS PC1 controller boards. The software above has been designed to accommodate upto four SPI interface boards at one time. Not to be reproduced without permission Page 16 of 18

17 LabView code has also been provided should the user require the use more than four interfaces. The software development has been left to the user in this case. This application control interface consists of a number announcement windows, control buttons and setup tabs. Unlike the single controller software detailed in section 5.2 this application does not allow the saving of data or its retrieval from data files. However, it is still possible to RESET, UPDATE and SAVE setup information to the control interface Running the Multi interface application for the first time Although the SPI interface controller board is supplied with the TEC current and voltage limits set to zero, the control setpoint voltage set to its mid position and the controller disabled it is a good idea to confirm these setting before connecting the interface to the PC1 controller board. This can be accomplished by leaving the TEC and thermistor unconnected while running the application program. Details about the application controls can be found in the next section Running the Multi interface application software To start the controller and control application do the following; Connect the PC1 and USB interface boards together Connect all appropriate connections to the PC1 board, PWR, TEC connections and thermistor connections. Connect the USB connector to the USB board and the PC ( N.B. the SPI board obtains power from the PC1 board) Select the PC1 controller program from the main program menu. It will automatically start. (The board will start up without the controller enabled as this is the saved state of the USB interface before dispatch). If you are unsure or the start up conditions are unknown it would be wise to disable the controller manually by shorting pin 2 to pin 4 on the J2 control input and then setting and updating/saving suitable limits settings to the SPI board before removing the shorting pin and using the application. The main screen consists of a number of control buttons placed vertically along the left hand side of the screen and some setup tabs that contain the setup data for the controller. The Control buttons have the following function; Not to be reproduced without permission Page 17 of 18

18 RESET: sets all control voltages to zero volts and sets the wiper on the spare potentiometer to one end of the scale. UPDATE: The PC1 USB interface is updated with the current settings (those outlined in the set up tabs). These setting are not held after subsequent power up. SAVE to PC1: saves the current settings to the PC1 USB memory. If powered down and then re-energised then the last saved setting will be present on the interface. STOP: Stops the application. The previous setting will be held until power down. At subsequent power up the previously saved settings (not the last updated settings) will be present on the interface First steps in setting up the multi interface There are a number of controller settings that MUST be implemented before turning on the controller in a real application. In order of importance these are; Set suitable TEC current and voltage limits. Failure to set suitable limits may result in the controller overdriving the TEC element and this may lead to component degradation or failure. Set suitable thermistor beta or Steinhart-Hart coefficients. Setting suitable coefficient will enable accurate temperature indication, within the specifications of the fitting algorithm. Set a suitable temperature setpoint. Enable or Disable the controller Using multiple boards It is sometimes difficult to keep track of which set of control parameters relate to which controller interface. It is advisable that the interface serial numbers are noted in some way so that easy identification can be accomplished. Not to be reproduced without permission Page 18 of 18

FT4232H-56Q Mini Module. USB Hi-Speed FT4232H Evaluation Module. Datasheet

FT4232H-56Q Mini Module. USB Hi-Speed FT4232H Evaluation Module. Datasheet Future Technology Devices International Ltd. FT4232H-56Q Mini Module USB Hi-Speed FT4232H Evaluation Module Datasheet Neither the whole nor any part of the information contained in, or the product described