DS89C420-QCL Datasheet, PDF (136/139 Pages) Maxim Integrated Products – Ultra-High-Speed Flash Microcontroller User’s Guide

Ultra-High-Speed Flash
Microcontroller User’s Guide
COMMAND SUMMARIES
B
Return the CRC-16 (cyclic redundancy check) of the internal ROM code. This self-CRC computation should always return 0000h.
C [begin-address [end-address]]
Return the CRC-16 (cyclic redundancy check) of the flash memory. This computation is performed over the range unless option-
al start and end addresses are given. The CRC-16 algorithm is commonly used in data communications. A blank device will return
the following checksum values: DS89C420/430: B001; DS89C440: 4040; DS89C450: 4400.
CX [begin-address [end-address]]
Return the CRC-16 (cyclic redundancy check) of the external RAM. This computation is performed over the range unless option-
al start and end addresses are given. The CRC-16 algorithm is commonly used in data communications.
D [begin-address [end-address]]
Dump flash memory in Intel hex format. An optional address range may be specified. Each record contains up to 32 data bytes.
The last line printed is the end-of-data record.
DX [begin-address [end-address]]
Dump external memory in Intel hex format. This command functions in the same manner as the D command with the exception
of the target memory being external.
K
Perform an erasure of the entire flash memory range, including security block, option control register, and bank-select bit.
L
Load standard ASCII Intel hex formatted data into flash memory. No lock bits may be set when attempting to load the internal flash
program memory. Only record types 00 and 01 are processed. Each record of the file is treated the same way. All characters are
discarded before the header character <:> is read. The rest of the record, defined by the length byte, is then processed. All char-
acters following the record checksum and prior to the next <:> are discarded. Control returns to the command prompt after an
Intel end record is encountered. Prior to programming each byte, the loader performs a preread of that flash memory location to
assess whether the new hex value can be written. After programming each byte, the loader reads the flash memory location again
to verify proper programming. The processing of each record is confirmed by an ACK/NAK response. New records should not be
transmitted until the ACK/NAK byte associated with the previous record has been received.
The ACK/NAK responses from the ROM loader are as follows:
A–Invalid address in Intel Hex record: Intel Hex record contains an address that exceeds the maximum internal flash memory or
encryption vector address (3Fh).
F–Flash controller error: An error was detected within the flash memory of the target device. Contact Dallas Semiconductor if the
device responds with repeated error messages of this type.
G–Good record: Record was received and programmed without error.
H–Invalid Intel Hex record format: Intel Hex record contains a nonhex character.
L–Invalid Intel Hex record length: Intel Hex record length exceeds allowable length [20 bytes (type 0); 0 bytes (type 1 EOF)].
P–Failure to write 1s to 0s during programming: Target flash memory was not erased prior to loading, or is programming a byte
more than once. Be sure to use the ROM loader K command before attempting to load new software. Also be sure that the Intel
Hex file does not reference more than one byte at the same location.
R–Invalid Intel Hex record type: ROM loader only accepts Intel Hex record types 00 and 01 in standard Intel Hex format; make
sure the assembler/compiler is not configured for Intel Extended Hex or HEX-386 format.
S–Invalid checksum in Intel Hex record: Intel Hex record contains a checksum that does not correspond to its hex record. This
error is caused by manual edits to the Intel Hex file or a compiler error.
V–Verify Error: Target flash memory does not match expected value. Erase memory and reprogram.
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