DS89C420-QCL Datasheet, PDF (135/139 Pages) Maxim Integrated Products – Ultra-High-Speed Flash Microcontroller User’s Guide

Ultra-High-Speed Flash
Microcontroller User’s Guide
Table 15-3. Alphabetic Commands (continued)
COMMAND
LX
R
V
VE
VX
W
^C
Load external RAM (Oh–FFFFh).
Read configuration.
Verify flash memory against incoming hex.
Verify encryption vector against incoming hex.
Verify external RAM against incoming hex.
Write register(s)
Reset loader.
FUNCTION
Selected commands require arguments and some commands have optional arguments. In all cases, arguments are expected to be
hexadecimal numbers. In addition, an ASCII control-C character (^C) causes the ROM loader to terminate any function currently being
executed and display the command line prompt. An incoming break character (defined as a received null character (00h) with the stop
bit = 0) causes the ROM loader to be restarted and the baud rate redetermined.
COMMAND LINE SYNTAX
Single-letter ASCII characters are recognized as commands by the ROM loader. Arguments are represented by hexadecimal numbers.
A hexadecimal number is any sequence of hexadecimal characters. A hexadecimal character may be a digit, 0 through 9, or one of
the letters A through F. A byte is always the right-most two digits of a hexadecimal number. An address is always the right-most four
digits of a hexadecimal number.
BYTE CONVERSION
A → 0AH
AB → 0ABH
ABC → 0BCH
ABCD → 0CDH
ADDRESS CONVERSION
A → 000AH
AB → 00ABH
ABC → 0ABCH
ABCD → 0ABCDH
ABCDE → 0BCDEH
The C, CX, D, and DX commands allow optional addresses to be entered. The syntax [begin-address [end-address]] is used to con-
vey the following meanings:
• No arguments: Begin-address is set to 0 and end-address is set to the range.
• One argument: Begin-address is set to the argument and end-address is set to the range.
• Two arguments: Begin-address is set to the first argument and end-address is set to the second argument. This second
address must not exceed the address value specified by the range.
In the second and third bullets above, an error message is generated if the end address is less than the begin address, either implic-
itly or explicitly. Error messages are transmitted as soon as errors are detected. All messages are preceded by the two characters E:,
and followed by a mnemonic description.
Commands are not processed until an entire command line is entered and terminated with a <CR>. No command line may be greater
than 17 bytes. Since a command line is not processed until a <CR> is entered, the <delete> character can be used to make edits.
Lines longer than 17 characters return an error message and no action is taken for that command line.
Only legal characters are echoed back by the loader. The legal characters are: 0123456789, <:>, <space>, ABCDE-
FGHIJKLMNOPQRSTUVWXYZ, and <delete>. Backspaces (<BS>) are converted to delete characters. The horizontal tab character is
converted to space. Lowercase alphabetic characters are converted to uppercase alphabetic.
The <delete> character is executed as a <BS> <space> <BS> when possible in command mode. This causes the character to be
overprinted on a hard-copy device. The <CR> character generates a <CR> <LF> pair.
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