1. EENG449b/Savvides Lec 7.1 2/3/05 Feb 2, 2005 Prof. Andreas Savvides Spring 2005 http://www.eng.yale.edu/courses/2005s/een g449b EENG 449b/CPSC 439b Computer Systems Lecture 7 ARM Assembly Programming and SOS

2. EENG449b/Savvides Lec 7.2 2/3/05 Announcements Programming assignment 1 out today –We will discuss it in class –Starting code Paper presentations –1: SOS & SOS programming –Simulators: ATEMU, AURORA and TOSSIM

3. EENG449b/Savvides Lec 7.3 2/3/05 Hello World Assembly Program

4. EENG449b/Savvides Lec 7.4 2/3/05 Some Definitions ADR – assembler pseudo instruction –Assembled into an ADD or SUB instruction EQU LDRB – load register byte LDRB r0,[r1] LDRB r0,[r1], #1 ; immediate value indexes into the array &0a – new line, &0d – carriage return SWI – Software Interrupt – puts the processor in supervisor mode and starts executing instructions from address 0x08

5. EENG449b/Savvides Lec 7.5 2/3/05 Branch Instructions Some of these are decided with the help of the program status register

6. EENG449b/Savvides Lec 7.6 2/3/05

7. EENG449b/Savvides Lec 7.7 2/3/05 Block Copy Program

8. EENG449b/Savvides Lec 7.8 2/3/05 Stacks and Subroutines LDMIA - Load Multiple Increment After

9. EENG449b/Savvides Lec 7.9 2/3/05 Load Store Multiple Instructions

10. EENG449b/Savvides Lec 7.10 2/3/05 Update Base Address Register with Load/Store Multiple Instructions

11. EENG449b/Savvides Lec 7.11 2/3/05 Example of Using Load/Store Multiple

12. EENG449b/Savvides Lec 7.12 2/3/05 Implementing a STACK Note that this does not exist in the ARM architecture we will implement it!

13. EENG449b/Savvides Lec 7.13 2/3/05 Pushing Onto Stack

14. EENG449b/Savvides Lec 7.14 2/3/05 STACK view of STM Instructions

15. EENG449b/Savvides Lec 7.15 2/3/05 POP Operation

16. EENG449b/Savvides Lec 7.16 2/3/05 Four Different Ways of Implementing a Stack

17. EENG449b/Savvides Lec 7.17 2/3/05 Relationship between the two different views of LDM/STM instructions

18. EENG449b/Savvides Lec 7.18 2/3/05 Subroutines

19. EENG449b/Savvides Lec 7.19 2/3/05 Subroutines

20. EENG449b/Savvides Lec 7.20 2/3/05 Nested Subroutines

21. EENG449b/Savvides Lec 7.21 2/3/05 Preserve things inside subroutine with STACK

22. EENG449b/Savvides Lec 7.22 2/3/05 Effect of Subroutine Nesting

23. EENG449b/Savvides Lec 7.23 2/3/05 Programming Assignment Let’s look into the programming assignment requirements Discussion items –Node architecture –UART setup inside the OKI processor –Connecting to the JTAG and Seehau –Burning your code in FLASH –Stepping through your code & resetting –Starting code for this assignment

24. EENG449b/Savvides Lec 7.24 2/3/05 Lab PlatformXYZ Sensor Node Sensor node created for experimentation –Low cost, low power, many peripherals –Integrated accelerometer, light and temperature sensor Part of a EENG449b project last semester Uses an IEEE 802.15.4 protocol –Chipcon 2420 radio OKI ARM Thumb Processor –256KB FLASH, 32KB RAM –Max clock speed 58MHz, scales down to 2MHz –Multiple power management functions Powered with 3AA batteries & has external connectors for attaching peripheral boards Designed at Yale Enalab and Cogent computer systems, will be used as the main platform for the course

25. EENG449b/Savvides Lec 7.25 2/3/05 XYZ’s Architecture

26. EENG449b/Savvides Lec 7.26 2/3/05 XYZ: Supervisor Circuitry & Low Power Sleep OKI μC RTC DS1337 Voltage Regulator 3 x AA batteries 2.5V 3.3V I2CI2C WAKEUP Enable Interrupt (SQW) DS1337 Real Time clock datasheet: http://pdfserv.maxim-ic.com/en/ds/DS1337.pdf Step 1: The μC selects the total time that wants to be turned off and programs the DS1337 accordingly, through the 2-wire serial interface. Step 2: The DS1337 turns-off the μC and uses its own crystal to keep the notion of time. Step 3: The DS1337 wakes up the μC after the programmed amount of time has elapsed. Note that the DS1337 RTC can disable the voltage regulator and completely turn-off the sensor node! In sleep mode, the whole device will consume around 60uW of power

27. EENG449b/Savvides Lec 7.27 2/3/05 XYZ: On Board Sensors Light Accelerometer Temperature OKI μC ADCADC AIN0 AIN1 AIN2 X Y PIOE5(EXINT0) 2-axis accelerometer datasheet (ADXL202E): http://www.rotomotion.com/datasheets/ADXL202E_a.pdf Temperature Sensor datasheet (TMP05): http://www.analog.com/UploadedFiles/Data_Sheets/192632828TMP05_6_prk.pdf Light Sensor datasheet (TSL251R): http://www.goblack.de/desy/digitalt/sensoren/tsl-250/tsl250r.pdf

28. EENG449b/Savvides Lec 7.28 2/3/05 OKI ARM ML675001/67Q5002/67Q5003 ARM7TDMI

29. EENG449b/Savvides Lec 7.29 2/3/05 FLASH Starts here External SRAM starts here Internal RAM starts here

30. EENG449b/Savvides Lec 7.30 2/3/05 Demo Example Using the JTAG Interface Hardware you need: –OKI L67Q4004 CPU board –Serial Cable –5V power supply –Optional: Seehau JTAG pod – only 2 available so you will need special arrangement to use this Software you need –Optional: Seehau debugger installed in CO-40 –Arm-gnu tools – installed in CO-40 »You can also install them on your own PC but you will not have access to the Seehau Debugger! »Visit the XYZ website http://www.eng.yale.edu/enalab/XYZhttp://www.eng.yale.edu/enalab/XYZ to get the tools

31. EENG449b/Savvides Lec 7.31 2/3/05 A Sample Makefile CFLAGS = -Wall -g -nostartfiles -mthumb-interwork -marm INCLUDE = -Iinc/ -Isrc/ OBJS = define.o common.o init.o irq.o pio_sample.o reentrant_irq.o LDFLAGS = -Wl,-Tarm.ld all: PIO.elf PIO.elf: $(OBJS) arm-elf-gcc $(CFLAGS) $(LDFLAGS) $(OBJS) $(LIBS) -o PIO.elf %.o: inc/%.s arm-elf-gcc -c $(INCLUDE) $(CFLAGS) $< %.o: src/%.c arm-elf-gcc -c $(INCLUDE) $(CFLAGS) $< %.o: src/%.s arm-elf-gcc -c $(INCLUDE) $(CFLAGS) $< %.bin: % arm-elf-objcopy -O binary $<.elf $@ clean: rm -f *.o PIO.elf PIO.hex hex: arm-elf-objcopy -I elf32-little -O ihex PIO.elf PIO.hex

32. EENG449b/Savvides Lec 7.32 2/3/05 The Linking Process After compiling the code, you need to link it. The linker script will specify the location in memory where your code will reside The start of the linker file looks like this: MEMORY { rom (rx) : ORIGIN = 0x00000000, LENGTH = 256K ram (rx) : ORIGIN = 0x50000000, LENGTH = 32K } /* section definition */ SECTIONS { …..

33. EENG449b/Savvides Lec 7.33 2/3/05 Application Development Cycle(Demo) Code Development Compile & Link Upload Code to Chip Run/Debug Linker determines Memory mapping (see arm.ld) File output format Can be elf, bin, hex.elf for JTAG Or.hex for serial port

34. EENG449b/Savvides Lec 7.34 2/3/05 Compiling your code To compile the code you simple run the makefile $ make The default output is a.elf file –You can use this with Nohau Seehau debugger BUT cannot be used with the OKI programming utility –To use the programming utilit you need to convert your file to intel hex format. »arm-elf-objcopy -I elf32-little -O ihex PIO.elf PIO.hex »Or type make hex in the sample Makefile

35. EENG449b/Savvides Lec 7.35 2/3/05 An Example Program for the OKI ARM PIO Program Posted on the website: Files in the inc directory: common.h - definitions specific to the board define.s - assembler common definitions – don’t need to change this irq.h - header files for interrupt functions – no change ml674000.h – include file for the OKI chip that lists the locations of registers – may need to change this for the 674Q4003 device

36. EENG449b/Savvides Lec 7.36 2/3/05 An Example Program for the OKI ARM PIO Program Posted on the website: init.s - chip initialization file. This initializes the exception table and interrupt handling mechanism – don’t need to change this reentrant_irq.s – interrupt handling mechanisms – don’t need to change this Files in the src directory: pio_sample.c - this is where the main() function. It is the entry point for any application. Pay attention to the initializations !!!