eeng449b/savvides lec 7.1 2/3/05 feb 2, 2005 prof. andreas savvides spring 2005 g449b eeng...

EENG449b/SavvidesLec 7.1

2/3/05

Feb 2, 2005

Prof. Andreas Savvides

Spring 2005

http://www.eng.yale.edu/courses/2005s/eeng449b

EENG 449b/CPSC 439b Computer Systems

Lecture 7

ARM Assembly Programming and SOS


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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


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Hello World Assembly Program


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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


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Branch Instructions

Some of theseare decided withthe help of the program status

register


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Block Copy Program


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Stacks and Subroutines

LDMIA - Load Multiple Increment After


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Load Store Multiple Instructions


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Update Base Address Register with Load/Store Multiple Instructions


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Example of Using Load/Store Multiple


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Implementing a STACK

Note that this does not exist in the ARM architecture we will implement it!


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Pushing Onto Stack


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STACK view of STM Instructions


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POP Operation


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Four Different Ways of Implementing a Stack


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Relationship between the two different views of LDM/STM

instructions


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Subroutines


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Nested Subroutines


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Preserve things inside subroutine with STACK


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Effect of Subroutine Nesting


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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


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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


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XYZ’s Architecture


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XYZ: Supervisor Circuitry & Low Power Sleep

OKI μC

RTC

DS1337

Voltage Regulator

3 x AA batteries

2.5V

3.3V

I2C

WAKEUP

EnableInterrupt (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


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XYZ: On Board Sensors

Light

Accelerometer

Temperature

OKI μC

A

D

C

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


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OKI ARM ML675001/67Q5002/67Q5003

ARM7TDMI


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FLASH Starts here

External SRAMstarts here

Internal RAMstarts here


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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/XYZ to get the

tools


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A Sample Makefile

CFLAGS = -Wall -g -nostartfiles -mthumb-interwork -marmINCLUDE = -Iinc/ -Isrc/

OBJS = define.o common.o init.o irq.o pio_sample.o reentrant_irq.oLDFLAGS = -Wl,-Tarm.ld

all: PIO.elf

PIO.elf: $(OBJS)arm-elf-gcc $(CFLAGS) $(LDFLAGS) $(OBJS) $(LIBS) -o PIO.elf

%.o: inc/%.sarm-elf-gcc -c $(INCLUDE) $(CFLAGS) $<

%.o: src/%.carm-elf-gcc -c $(INCLUDE) $(CFLAGS) $<

%.o: src/%.sarm-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


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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{…..


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Application Development Cycle(Demo)

Code Development

Compile & Link

Upload Code to Chip

Run/Debug

Linker determinesMemory mapping

(see arm.ld)

File output formatCan be elf, bin, hex

.elf for JTAGOr

.hex for serial port


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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


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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 thisirq.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


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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 thisreentrant_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 !!!

eeng449b/savvides lec 7.1 2/3/05 feb 2, 2005 prof. andreas savvides spring 2005 g449b eeng...

Documents

eeng449bsavvides lec

stack slide

assignment slide

sos slide

tossim slide

course slide

loadstore multiple slide

address 0x08 slide