Maxim Integrated MAXQ7667 - Manual (Page 228)

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MAXQ7667 User’s Guide
All commands in Family 0 can be executed without first matching the password. All other commands (in Families 1x through Fx) are
password protected; the password must first be matched before these commands can be executed.
A special case exists when the program memory has not been initialized (following master erase). If the password (stored in word locations
0010h to 001Fh in program memory) is all 0000h words or all FFFFh words, the bootloader treats the password as having been matched.
This allows access to password-protected commands following master erase (when no password has been set in program memory).
When providing addresses for code or data read or write to bootloader commands, all addresses run from 0000h to (memory size–1).
Due to the buffer between TDI and TDO (when using the JTAG port), there is always an output when data is put in. Therefore, for com-
mands that do not require a response, the data out is not relevant and should be ignored (for example, exit loader, input 01h).
Another important point to note, when using the JTAG port, is that the data is pushed out sequentially. To get a relevant data output a
series of no operation (Command 00h) should be pushed in to get the data out. For example, the code command 04h has two outputs:
byte 1 is flags and byte 2 is status code. Hence, the data that goes in must have
Operation cmd #2, for pushing data out> , or, in other words, 04 00 00 00. The data that comes
out is valid after the and , and will be in the order byte 1 is flags and byte 2 is
status code.
13.3.8 Family E Commands: Erase Fixed Length (Password Protected)
Command E0h—Erase Code Fixed Length
This command erases (programs to FFFFh) a 64-byte block of the program flash memory. The address given should be located in the
block to be erased.
Command E1h—Erase Data Fixed Length
This command erases a single word/byte in data RAM to zero at (AddressH:AddressL) to zero.
I/O Byte 1 Byte 2 Byte 3 Byte 4
Input E1h 0 AddressL AddressH
Output
I/O Byte 1 Byte 2 Byte 3 Byte 4
Input E0h 0 AddressL AddressH
Output