MOTOROLA
10-20
DEVELOPMENT SUPPORT
CPU16
REFERENCE MANUAL
10.4.10 BDM Command Set
The BDM command set is summarized in
Table 10-5
. Subsequent pages contain a
BDM command glossary. Glossary entries are in the same order as the table. Each
entry contains detailed information concerning commands and results, and includes a
command sequence diagram.
10.4.10.1 BDM Memory Commands and Bus Errors
If a bus error occurs while a BDM command that accesses memory (RDMEM, WD-
MEM, RPMEM, or WPMEM) is executing, it is ignored by the CPU16. Data returned
by a read access during which a bus error occurs is indeterminate.
Table 10-5 Command Summary
Command
Read Registers
from Mask
Write Registers
from Mask
Read MAC Registers
Mnemonic
RREGM
Description
Read contents of registers specified by
command word register mask
Write to registers specified by
command word register mask
Read contents of entire
multiply and accumulate register set
Write to entire multiply and accumulate register set
Read contents of program counter and stack pointer
Write to program counter and stack pointer
Read data from specified 20-bit address
in data space
Write data to specified 20-bit address
in data space
Read data from specified 20-bit address
in program space
Write data to specified 20-bit address
in program space
Instruction pipeline flushed and refilled;
instructions executed from current PC – $0006
Null command — performs no operation
WREGM
RDMAC
Write MAC Registers
Read PC and SP
Write PC and SP
Read Data Memory
WRMAC
RPCSP
WPCSP
RDMEM
Write Data Memory
WDMEM
Read Program Memory
RPMEM
Write Program Memory
WPMEM
Execute from current
PK: PC
Null Operation
GO
NOP
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