Using Jtager

Introduction
JTAGER has not been updated for a while but is a great program. It comes with support for the ARM7TDMI built in but only supports wiggler jtag hardware.

JTAGER is useful for debugging and downloading binary files to the JB. See JuiceBox Code Test for demo programs.

Install
Download the tarball from http://jtager.sourceforge.net/

Read the README file for install instructions (./configure && make && make install should do it)

Usage
This will take you through running the lcd_2 demo on your Juicebox using JTAGER. Note that I am using # for comments but this is not actually valid - it is just to clarify what the command is doing.

JTAGER> help
 * 1) see available commands
 * snip - see your output from this*

JTAGER> halt Requesting HALT target ... [OK] The target is halted in ARM mode.
 * 1) halt the CPU

JTAGER> idcode Device ID = 0x1F0F0F0F bit[0] = 1, always be 1, required by IEEE Std 1149.1 Manufacturer (bit[11:1]): 0x787 - SAMSUNG Part number (bit[27:12]): 0xF0F0 Version (bit[31:28])   : 0x1
 * 1) Verify the CPU

JTAGER> memset --base=0x0c001000 --infile=hacking/juicebox/jb-code/lcd_2.bin memset: Fill the memory block [0x0C001000, 0x0C0017EB] with the file "hacking/juicebox/jb-code/lcd_2.bin" ... . [OK] Total 2028 bytes are written.
 * 1) Copy the lcd_2 demo to memory (you have to hit enter twice)
 * 2) be sure to copy the BIN file and not the ELF file

JTAGER>JTAGER> restart 0x0c001000 Restarting the target processor at 0x0C001000
 * 1) restart the proc at the correct entry point

That's it You should now be looking at the LCD demo starting with the text "Juicebox LCD Demo #2" on the screen.

What is going on here?
Read the lcd_2.dld file from the lcd_2 tarball - this gives a clue as to where to copy the BIN file.

/* Memory Definitions */ MEMORY { RAM (rw) : ORIGIN = 0x0c001000, LENGTH = 0x00010000 SRAM (rw) : ORIGIN = 0x010001000, LENGTH = 0x1000

}

The Juicebox memory (RAM) starts at 0x0c001000 - therefore that is where we copy the BIN to.

Now that you can copy binaries to your juicebox and run them it's time to start writing your own code. See JuiceBox Software Development for help.