Maxim Integrated DS4830A Optical Microcontroller - Manual (Page 167)

DS4830A User’s Guide
167
Table 21-2: Background Mode Commands
OPCODE COMMAND OPERATION
0000-0000 No Operation No operation. (Default state for Debug Shift register).
0000-0001 Read ICDC
Read control data from the ICDC. The contents of the ICDC register will be loaded into the Debug
Shift Register via the ICDB register for host read. This command requires one follow-on transfer
cycle.
0000-0010 Read ICDF
Read flags from the ICDF. The contents of the ICDF register (one byte) will be loaded into the
Debug Shift Register via the ICDB register for host read. This command requires one follow-on
transfer cycle.
0000-0011 Read ICDA
Read data from the ICDA. The contents of the ICDA register will be loaded into the Debug Shift
Register via the ICDB register for host read. This command requires two follow-on transfer cycles
with the least significant byte first.
0000-0100 Read ICDD
Read data from the ICDD. The contents of the ICDD register will be loaded into the Debug Shift
Register via the ICDB register for host read. This command requires two follow-on transfer cycles
with the least significant byte first.
0000-0101 Read BP0
Read data from the BP0. The contents of the BP0 register will be loaded into the Debug Shift
Register via the ICDB register for host read. This command requires two follow-on transfer cycles
with the least significant byte first.
0000-0110 Read BP1
Read data from the BP1. The contents of the BP1 register will be loaded into the Debug Shift
Register via the ICDB register for host read. This command requires two follow-on transfer cycles
with the least significant byte first.
0000-0111 Read BP2
Read data from the BP2. The contents of the BP2 register will be loaded into the Debug Shift
Register via the ICDB register for host read. This command requires two follow-on transfer cycles
with the least significant byte first.
0000-1000 Read BP3
Read data from the BP3. The contents of the BP3 register will be loaded into the Debug Shift
Register via the ICDB register for host read. This command requires two follow-on transfer cycles
with the least significant byte first.
0000-1001 Read BP4
Read data from the BP4. The contents of the BP4 register will be loaded into the Debug Shift
Register via the ICDB register for host read. This command requires two follow-on transfer cycles
with the least significant byte first.
0000-1010 Read BP5
Read data from the BP5. The contents of the BP5 register will be loaded into the Debug Shift
Register via the ICDB register for host read. This command requires two follow-on transfer cycles
with the least significant byte first.
0001-0001 Write ICDC
Write control data to the ICDC. The contents of ICDB will be loaded into the ICDC register by the
debug engine at the end of the data transfer cycle.
0001-0011 Write ICDA
Write data to the ICDA. The contents of ICDB will be loaded into the ICDA register by the debug
engine at the end of the data transfer cycles. Data is transferred with the least significant byte first.
0001-0100 Write ICDD
Write data to the ICDD. The contents of ICDB will be loaded into the ICDD register by the debug
engine at the end of data transfer cycles. Data is transferred with the least significant byte first.
0001-0101 Write BP0
Write data to the BP0. The contents of ICDB will be loaded into the BP0 register by the debug
engine at the end of data transfer cycles. Data is transferred with the least significant byte first.
0001-0110 Write BP1
Write data to the BP1. The contents of ICDB will be loaded into the BP1 register by the debug
engine at the end of data transfer cycles. Data is transferred with the least significant byte first.
0001-0111 Write BP2
Write data to the BP2. The contents of ICDB will be loaded into the BP2 register by the debug
engine at the end of data transfer cycles. Data is transferred with the least significant byte first.
0001-1000 Write BP3
Write data to the BP3. The contents of ICDB will be loaded into the BP3 register by the debug
engine at the end of data transfer cycles. Data is transferred with the least significant byte first.
0001-1001 Write BP4
Write data to the BP4. The contents of ICDB will be loaded into the BP4 register by the debug
engine at the end of data transfer cycles. Data is transferred with the least significant byte first.
0001-1010 Write BP5
Write data to the BP5. The contents of ICDB will be loaded into the BP5 register by the debug
engine at the end of data transfer cycles. Data is transferred with the least significant byte first.
0001-1111 Debug
Debug command. This command forces the debug engine into debug mode and halts the CPU
operation at the completion of the current instruction after the debug command is recognized by the
debug engine.
21.1.1 – Breakpoint Registers
The DS4830A incorporates six breakpoint registers (BP0–BP5) that are configurable by the host for establishing
different types of breakpoint mechanisms. The first four breakpoint registers (BP0–BP3) are 16-bit registers that are
configurable as program memory address breakpoints. When enabled, the debug engine will force a break when a
match between the breakpoint register and the program memory execution address occurs. The final two 16-bit
breakpoint registers (BP4, BP5) are configurable in one of two possible capacities. They may be configured as data
memory address breakpoints or may be configured to support register access breakpoints. In either case, if
breakpoints are enabled and the defined breakpoint match occurs, the debug engine will generate a break condition.
The six breakpoint registers are documented below.