1. JTAG, Multi-ICE and Angel
Speaker :沈文中
National Taiwan University
Adopted from National Taiwan University
SOC Course Material

2. Outline ARM debug Architecture Content of JTAG Content of Embedded ICE
Multi-ICE Arch.
Angel Arch.

3. ARM debug Arch.(I) AXD can debug design through: ARMulator(software)
Multi-ICE(hardware)
Angel(hardware)

4. ARM debug Arch.(II) Limits of ARMulator Processor core model
Memory interface
Coprocessor interface
Operating system interface

5. ARM debug Arch.(III) Multi-ICE The solution for ARMulator limits
Can emulate custom logic
Use hardware to emulate truly results
Extended from JTAG Architecture

6. ARM debug Arch.(IV) Angel A hardware can be real-Monitor interface
Angel communicates using ADP
Allow multiple indep. sets of messages to share a communications link

7. Outline ARM debug Architecture Content of JTAG Content of Embedded ICE
Multi-ICE Arch.
Angel Arch.

8. JTAG Arch. Serial scan path from one cell to another
Controlled by TAP controller

9. JTAG principle(I)

10. JTAG Principle(II) JTAG Signals TRST Test reset signal
TDI Test data in
TMS Test mode select
TCK Test clock
TDO Test data out

11. EmbeddedICE interface
Pin
Name
Function 1
SPU
System powered up, pin connected to Vdd through a 33 ohm resistor 3
nTRST
Test reset, active low 5
TDI
Test data in 7
TMS
Test mode select 9
TCK
Test clock 11
TDO
Test data out 12
nICERST
Target System Reset (sometimes referred to nSYSRST or nRSTOUT) 13
2, 4, 6, 8,10,14
VSS
System ground reference (All VSS pins should be con-nected

12. Outline ARM debug Architecture Content of JTAG Content of Embedded ICE
Multi-ICE Arch.
Angel Arch.

13. Debug extensions to the ARM core
The extensions consist of a number of scan chains around the processor core and some additional signals that are used to control the behavior of the core for debug purposes :
BREAKPT: enables external hardware to halt processor execution for debug purposes.active high
DBGRQ: is a level-sensitive input that causes the CPU to enter debug state when the current instruction has completed.
DBGACK: is an output from the CPU that goes high when the core is in debug state

14. The EmbeddedICE logic
This logic is the integrated onchip logic that provides JTAG debug support for ARM core.
This logic is accessed through the TAP controller on the ARM core using the JTAG interface. Consists of:
Two watchpoint units
A control register
A status register
A set of registers implementing the Debug Communications Channel link

15. Watch /break point
Watchpoints are taken when the data being watchpointed has changed.
Breakpoints are taken when the instruction being breakpointed reaches the execution stage. the program counter is not updated, and retains the address of the breakpointed instruction.

16. Outline ARM debug Architecture Content of JTAG Content of Embedded ICE
Multi-ICE Arch.
Angel Arch.

17. Multi-ICE(I)

18. Multi-ICE(II)
Debugging software can be run on different computer through Network.
Debugger can be run in different computers

19. The portmap application
To support network connections, an additional application must be running on the windows workstation that runs the The multi-ICE server.
the portmapper allows software on other computers on the network to locate the The multi-ICE server.

20. How multi-ICE differs from a debug monitor
A debug monitor is an application that runs on your target hardware in conjunction with your application, and requires some resources(ex:memory) to be avaible
The EmbeddedICE debug arch. Requires almost no resources. Rather than being an application on the board, it works by using :
Additional debug hardware within the core, parts that enable the host to communicate with the target
An external interface unit that buffers and translates the core signals into something usable by a host computer

21. Outline ARM debug Architecture Content of JTAG Content of Embedded ICE
Multi-ICE Arch
Angel Arch.

22. Angel (I)
Angel system
Debugger: Running on the host computer, giving instructions to Angel and displaying the results obtained from it.
Angel debug monitor: Running alongside the application being debugged on the target platform.
Armsd: The command line must be of the form:
armsd –adp –port s=1 –linespeed image.axf

23. Angel (II) Debug support C library semihosting support
Reporting and modifying memory and processor status
Downloading applications to the target system
Setting breakpoints
C library semihosting support
Enabling applications linked the ARM C and C++ libraries to make semihosting requests by SWI
Communications support
Using ADP for communicates
Providing an error-correcting communications protocol.

24. Angel (III)
Angel’s communications diagram

25. Angel (IV) Task management
Ensuring that only a single operation is carried out at any time
Assigning task priorities and schedules tasks accordingly
Controlling the Angel environment processor mode

26. Angel(V) Exception handling SWI
Installing it to support semihosting requests , to allow applications and Angel to enter Supervisor mode
Undefined
Using 3 undefined instructions to set breakpoints in code
Data, Prefetch Abort
Reporting the exception to the debugger, suspend the application, and pass control back to the debug
FIQ,IRQ
Enabling Angel communications to run off, or both types of interrupt.

27. Lab 6: JTAG and Multi-ICE
Goal
Set up the hardware and the software of Multi-ICE unit and target board.Use Multi-ICE to debug.
Principles
Basic debug skill
Debugger-Target Interface
Guidance
Overview of examples used in the Steps
Steps
Multi-ICE connects the parallel port of a workstation to the JTAG interfaces of an ASIC
Angel debug monitor uses a serial line or Ethernet to communicate with a development host running an ARM debugger.
Requirements and Exercises
Write a lotto program that generates N sets of number. The user can specify:
Number of the set: N.
The numbers must be included in these N sets of number
The numbers must not be included in these N sets of number
Discussion
What’s different between with ARMulator and MultiICE or ARMulator and Angel that we do the debugging task.

28. Reference Topic & Related Documents
Multi-ICE [DUI_0048F_MICE2_2_UG]
AXD and armsd Debuggers Guide [DUI_0066D_AXDDG_2_UG ]
Getting Started Guide [DUI_0064D_GSG_UG ]
AFS_Referece_Guide