NXP Semiconductors
UM11227
NTM88 family of tire pressure monitor sensors
UM11227 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2020. All rights reserved.
User manual Rev. 6 — 24 April 2020
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8.5.5 BGND instruction
The BGND instruction is new to the HCS08 compared to the M68HC08. BGND would
not be used in normal user programs because it forces the CPU to stop processing
user instructions and enter the ACTIVE BACKGROUND mode. The only way to resume
execution of the user program is through reset or by a host debug system issuing a GO,
TRACE1, or TAGGO serial command through the BACKGROUND DEBUG interface.
Software-based breakpoints can be set by replacing an opcode at the desired breakpoint
address with the BGND opcode. When the program reaches this breakpoint address, the
CPU is forced to ACTIVE BACKGROUND mode rather than continuing the user program.
8.6 HCS08 instruction set summary
8.6.1 Instruction set summary nomenclature
The nomenclature listed here is used in the instruction descriptions in Table 7.
8.6.2 Operators
( ) = Contents of register or memory location shown inside parentheses
← = Is loaded with (read: "gets")
& = Boolean AND
| = Boolean OR
⊕
= Boolean exclusive-OR
× = Multiply
÷ = Divide
: = Concatenate
+ = Add
– = Negate (two’s complement)
8.6.3 CPU registers
A = Accumulator
CCR = Condition code register
H = Index register, higher order (most significant) 8 bits
X = Index register, lower order (least significant) 8 bits
PC = Program counter
PCH = Program counter, higher order (most significant) 8 bits
PCL = Program counter, lower order (least significant) 8 bits
SP = Stack pointer
8.6.4 Memory and addressing
M = A memory location or absolute data, depending on addressing mode
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