Maxim Integrated MAX31782 - Manual (Page 144)

MaximIntegrated 17-9
MAX31782 User’s Guide
Revision 0; 8/11
Table17-3.DebugModeCommands
OPCODE COMMAND OPERATION
0010–0000 No Operation Nooperation.
0010–0001
Read register
Map
Readdatafrominternalregisters.This command forces the debug engine to update the
CMD[3:0] bits in the ICDC to 0001b and perform a jump to ROM code at x8010h . The ROM debug
service routine loads register data to ICDB for host capture/read, starting at the lowest register
location in module 0, one byte at a time in a successive order until all internal registers are read
and output to the host .
0010–0010
Read data
memory
Readdatafromdatamemory. This command requires four follow-on transfer cycles, two for the
starting address and two for the word read count, starting with the LSB address and ending with
the MSB read count . The input address must be based memory map when executing from utility
ROM, as shown in Figure 2-4 . The address is moved to the ICDA register and the word read count
is moved to the ICDD register by the debug engine . This information is directly accessible by the
ROM code . At the completion of this command period, the debug engine updates the CMD[3:0]
bits to 0010b and performs a jump to ROM code at x8010h . The ROM debug service routine loads
ICDB from data memory according to address and count information provided by the host .
0010–0011
Read pro-
gram stack
Readdatafromprogramstack. This command requires four follow-on transfer cycles, two for
the starting address and two for the read count, starting with the LSB address and ending with
the MSB read count . The address is moved to the ICDA register and the read count is moved to
the ICDD register by the debug engine . This information is directly accessible by the ROM code .
At the completion of this command period, the debug engine updates the CMD[3:0] bits to 0011b
and performs a jump to ROM code at x8010h . The ROM debug service routine pops data out from
the stack according to the information received in the ICDA and ICDD register .
The address input
is the highest value that is used, as words are popped off the stack and returned in descending
order .
0010–0100 Write register
Writedatatoaselectedregister. This command requires four follow-on transfer cycles, two for
the register address and two for the data, starting with the LSB address and ending with the MSB
data . The address is moved to the ICDA register and the data is moved to the ICDD register by
the debug engine . This information is directly accessible by the ROM code . At the completion of
this command period, the debug engine updates the CMD[3:0] bits to 0100b and performs a jump
to ROM code at x8010h . The ROM debug service routine updates the select register according
to the information received in the ICDA and ICDD registers .
Any register location can be written
using this command, including reserved locations and those used for op code support . No protec-
tion is provided by the debugging interface, and avoiding side effects is the responsibility of the
host system communicating with the MAX31782 . Writing to the IP register alters the address that
execution resumes from when the debugging engine exits .
0010–0101
Write data
memory
Writedatatoaselecteddatamemorylocation. This command requires four follow-on transfer
cycles, two for the memory address and two for the data, starting with the LSB address and ending
with the MSB data . The input address must be based memory map when executing from utility ROM,
as shown in Figure 2-4 . The address is moved to the ICDA register and the data is moved to the
ICDD register by the debug engine . This information is directly accessible by the ROM code . At the
completion of this command period, the debug engine updates the CMD[3:0] bits to 0101b and per-
forms a jump to ROM code at x8010h . The ROM debug service routine updates the selected data
memory location according to the information received in the ICDA and ICDD registers .
0010–0110 Trace
Tracecommand. This command allows single stepping the CPU and requires no follow-on trans-
fer cycle . The trace operation is a ‘debug mode exit, one cycle CPU execution, debug mode entry’
sequence .
0010–0111 Return
Returncommand. This command terminates the debug mode and returns the debug engine to
background mode . This allows the CPU to resume its normal operation at the point where it has
been last interrupted .