1 Built-In Test Software for Deformable Mirror High Voltage Drivers Jianwei Zhou Home Institution: University of Hawaii at Manoa CfAO Akaimai Intership 2008 Subaru Telescope Mentor: Stephen Colley Funding provided by the Center for Adaptive Optics through its National Science Foundation Science and Technology Center grant (#AST )

2 Today’s Presentation Background Info Design Discussion Problems (Solved& Unsolved) Results

3 Acronyms A/D – Analog to Digital D/A – Digital to Analog BIT- Built-In Test DM- Deformable Mirror HV – High Voltage ICD – In-Circuit Debugger I2C – Inter-Integrated Circuit LGSAO – Laser Guide Star Adaptive-Optics

4 Project Overview Design Built-In Test (BIT) software for deformable mirror high voltage driver in the Subaru LGSAO system. Measurement performed by BIT circuitry Input Voltages Output Voltages Power Supply Voltages Board Temperature

5 Deformable Mirror (DM) DM is used with wavefront sensor to provided optical control and correction. DM operates with maximum voltages of +400V, and HV amplifiers with gain of 40 are used to amplify input voltages of + 10v to +400v.

6 HV Driver Subsystem The HV driver subsystem in the Subaru LGSAO system consist of 10 HV Amplifier boards

7 High Voltage Amplifier Board High Voltage Amplifier Board

8 Low Voltage Connector LV Input LV Power BIT Network Differential Input Amplifiers HV Amplifiers Amplifiers Low Voltage Regulator Power LV Dividers HV Dividers Amplifiers High Voltage Connector HV Input HV Power MUX AD Converter MC Build In Test

9 Real-Time Control Computer D/A Converter Board HV Amplifier Board w/BIT DM v v Digital Data Importance of Built-In Test Software

10 Built-In Test Circuit Main components: Analog Multiplexer Analog-To-Digital Converter Microcontroller (PIC 16F877) Temperature Sensor Mux A/D Converter Microcontroller Temperature Sensor Host Computer BIT Circuit

11 Programming Program Language use: C Step 1: Program in C Step 2: Compile to Assembly language by PICC STD. Pros and cons C is easier and much shorter than assembly language Debugging require the knowledge of microcontroller

12 Programming MAIN+PORT+ MUX+ADC+I2C+TEMP 5 Functions total:

13 Set Up Problem: The C compiler cannot installed and compiled properly Solution: Read the user manual and get help from product website

14 Memory Constraint of Microcontroller Problems: Programs must fit in the available on-chip program memory ( very small compare to computer) Solution: Must optimize the code to reduce the memory I Displayed the measurement as character instead of int (char 8 bit, int 32 bits) II Reduced the number of variable III Reduced the lines of code whenever possible

15 Low Level Programming Problems: Must understand the characteristic of the hardware when programming Solution: Reading the data sheet of the hardware.

16 Debugging In-Circuit Debugger

17 MPLAB IDE

18 Results Tested the BIT circuit 1 bad A/D converter is found in one board Fabrication error is found( The pin layout of temperature sensor on the board is different from the schematic diagram) Measures the input voltages, output voltages, and power supply voltages by the BIT software on a HV amplifier board A bug in the PICC STD is found ( cannot insert leading 0 with sprintf function)

19 Work To Be Completed Run the BIT software in the whole LGSAO system Communication between the BIT circuit and host computer (I2C)

20 Personal Thought A valuable opportunity to learn about circuit design Application of the knowledge learnt in school to real life practice Increased research ability Increased Confidence

21 Acknowledgements Stephen Colley, Mentor Sarah Anderson, Hawaii Island Internship Coordinator Lynne Raschke, Science Communication Lead Instructor Scott Seagroves, Science Communication Co-instructor Lisa Hunter, Akamai Intership Director

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