PC87591L-N05 Datasheet, PDF (398/401 Pages) National Semiconductor (TI) – LPC Mobile Embedded Controller

C. Booter Program (Continued)
Debugging limitations:
• No hardware reset.
• Debugging transactions are triggered by a maskable interrupt (instead of the ISE trap used in JTAG).
• Low data transfer speed.
C.3.2 JTAG Connection
If the JTAG connection is used, connect these five pins:
• TDI
• TDO
• TMS
• TCK
• TINT
To connect through JTAG, the PC87591L-N05 must boot in OBD environment. This means that the ENV1 strap pin must be
pulled up.
Resources needed:
• The host system must be equipped with a JTAG device.
• CR16B debugging tools must be installed.
Debugging limitations:
• The chip must be in OBD environment.
• Five pins must be connected (compared to two pins for the RS-232 connection).
C.4 MONITOR MEMORY WRITES
Monitor memory writes are divided into two groups:
• Internal memory writes from addresses 0000₁₆ - 0FFF₁₆ (Internal ROM - however the ROM cannot be written) and
E000₁₆ - FFFF₁₆ (Internal RAM and I/O-mapped registers); these are normal memory writes.
• External memory writes (from addresses 1000₁₆ - DFFF₁₆ and 10000₁₆ and higher); there are three configurable
working modes that affect the memory writes to these addresses
Working Modes
The working mode is selected by the byte-wide RAM register placed at address F7FE₁₆.
There are three working modes:
• Eprom mode, selected by writing 01₁₆ to the RAM register (default).
The monitor performs the following JEDEC-compatible algorithm for each byte; when writing value XX at address YY
the monitor:
— When the external flash bus width is eight bits:
1. Writes AA₁₆ to address 5555₁₆.
2. Writes 55₁₆ to address 2AAA₁₆.
3. Writes A0₁₆ to address 5555₁₆.
4. Writes XX to address YY.
— When the external flash bus width is 16 bits:
1. Writes AA₁₆ to address AAAA₁₆.
2. Writes 55₁₆ to address 5554₁₆.
3. Writes A0₁₆ to address AAAA₁₆.
4. Writes XX to address YY.
Note: The Booter auto-detects the flash bus width if the flash device is JEDEC compatible.
• Normal mode, selected by writing 02₁₆ to the RAM register:
The monitor performs a normal write (i.e. writes XX to address YY).
This mode is recommended when external memory is mapped to a RAM device.
• Generic mode, selected by writing 03₁₆ to the RAM register:
The monitor calls a function placed in the RAM at address F400₁₆ with all parameters. This function should perform the
memory write. The function prototype is:
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