Transcript Lecture 1: Course Introduction and Review

EENG 449b/CPSC 439b
Computer Systems
Lecture 7
ARM Assembly Programming and SOS
Feb 2, 2005
Prof. Andreas Savvides
Spring 2005
http://www.eng.yale.edu/courses/2005s/een
g449b
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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 these
are decided with
the 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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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
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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
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Part of a EENG449b project last
semester
Uses an IEEE 802.15.4 protocol
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Chipcon 2420 radio
OKI ARM Thumb Processor
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Low cost, low power, many peripherals
Integrated accelerometer, light and
temperature sensor
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
2.5V
Voltage Regulator
3.3V
Enable
Interrupt (SQW)
3 x AA
batteries
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RTC
DS1337
OKI μC
WAKEUP
I2C
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
DS1337 Real Time clock datasheet: http://pdfserv.maxim-ic.com/en/ds/DS1337.pdf EENG449b/Savvides
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XYZ: On Board Sensors
AIN0
Light
Accelerometer
A
X
AIN1
Y
AIN2
D
C
OKI μC
Temperature
PIOE5(EXINT0)
Light Sensor datasheet (TSL251R): http://www.goblack.de/desy/digitalt/sensoren/tsl-250/tsl250r.pdf
Temperature Sensor datasheet (TMP05):
http://www.analog.com/UploadedFiles/Data_Sheets/192632828TMP05_6_prk.pdf
2-axis accelerometer datasheet (ADXL202E): http://www.rotomotion.com/datasheets/ADXL202E_a.pdf
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OKI ARM ML675001/67Q5002/67Q5003
ARM7TDMI
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External SRAM
starts here
Internal RAM
starts here
FLASH Starts here
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Demo Example Using the JTAG
Interface
• Hardware you need:
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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 -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
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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
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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)
ram (rx)
}
: ORIGIN = 0x00000000, LENGTH = 256K
: ORIGIN = 0x50000000, LENGTH = 32K
/* section definition */
SECTIONS
{
…..
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Application Development Cycle(Demo)
Code Development
Compile & Link
Linker determines
Memory mapping
(see arm.ld)
File output format
Can be elf, bin, hex
Upload Code to Chip
.elf for JTAG
Or
.hex for serial port
Run/Debug
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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 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
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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 this
reentrant_irq.s – interrupt handling mechanisms –
don’t need to change this
Files in the src directory:
pio_sample.c
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- this is where the main() function.
It is the entry point for any
application. Pay attention to the
initializations !!!
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