Week 1: Toolchain & gdb (ch. 2,3)

Question 1

What is needed on the development platform for you to interact with gdb to communicate with the device programmer?

Answer 1

• a gdb program that is compatible with the target processor
• a gdb-server programmer that can translate gdb requests to commands understandable by the device programmer

Question 2

What are the 4 phases of microprocessor program development?

Answer 2

• Assembly/compile time
  
  • user-created assembly code gets processed to make machine code and data
• Linking
  
  • assembled programs combined into a memory image file
• Loading
  
  • memory image file loaded into processor memory
• Execution/run-time
  
  • processor executes loaded program in memory
  • program counter becomes relevant now

Question 3

What is openocd?

Answer 3

• functions as a gdb-server, so that gdb commands can be interpreted and requests sent to the hardware programmer to retrieve and return requested info to a gdb session
• provides facilities for in-circuit programming and on-chip debugging

Question 4

What components make up a typical cross-platform development environment?

Answer 4

1. Development Platform (Linux or Windows, where dev tools run)
2. Device Programmer (intermediary hardware programming device, vendor-supplied, providing in-circuit programming support)
3. Target Processor (memory image file loaded for here execution)

Question 5

What is the toolchain? What components does this one have?

Answer 5

• all programs needed to develop software
  
  • assembler (as)
  • compiler (gcc)
  • linker (ld)
  • debugger (gdb)
  • utility commands (objcopy, objdump)
• used on the development platform to develop code for target processor

Question 6

What is in-circuit programming?

Answer 6

Moving code to the target platform

(device programmer provides in-circuit programming support)

Question 7

How does gdb communicate with a gdb-server (openocd)?

Answer 7

via tcp/ip (telnet) or named pipes

Question 8

Explain what the gdb-server programmer module is responsible for.

Answer 8

• It is the intermediary in the development platform that can translate gdb requests to commands understandable by the vendor device programmer
• Communicates with device programmer (has device driver support)
• openocd software does all of this

Question 9

What is cross-platform development?

Answer 9

Developing code on a different processor than the one it is intended to run on

Question 10

What does it mean when code is cross-compiled?

Answer 10

• developed and compiled on one platform to run on another
• using arm-none-eabi-gcc command

Question 11

Once all hardware components are in place in the dev environment, what is the purpose of a host program on the development platform?

Answer 11

To interact with the target processor: programming or debugging