NXP Semiconductors
FXTH87E
FXTH87E, Family of Tire Pressure Monitor Sensors
17.2.3 BDC commands
BDC commands are sent serially from a host computer to the BKGD/PTA4 pin of
the target HCS08 MCU. All commands and data are sent MSB-first using a custom
BDC communications protocol. ACTIVE BACKGROUND mode commands require
that the target MCU is currently in the ACTIVE BACKGROUND mode while non-
intrusive commands may be issued at any time whether the target MCU is in ACTIVE
BACKGROUND mode or running a user application program. Table 165 shows all
HCS08 BDC commands, a shorthand description of their coding structure, and the
meaning of each command.
17.2.3.1 Coding structure nomenclature
This nomenclature is used in Table 165 to describe the coding structure of the BDC
commands. Commands begin with an 8-bit hexadecimal command code in the host-to-
target direction (most significant bit first)
/ = separates parts of the command
d = delay 16 target BDC clock cycles
AAAA = a 16-bit address in the host-to-target direction
RD = 8 bits of read data in the target-to-host direction
WD = 8 bits of write data in the host-to-target direction
RD16 = 16 bits of read data in the target-to-host direction
WD16 = 16 bits of write data in the host-to-target direction
SS = the contents of BDCSCR in the target-to-host direction (STATUS)
CC = 8 bits of write data for BDCSCR in the host-to-target direction (CONTROL)
RBKP = 16 bits of read data in the target-to-host direction (from BDCBKPT breakpoint
register)
WBKP = 16 bits of write data in the host-to-target direction (for BDCBKPT breakpoint
register)
Table 165.ꢀBDC command summary
Active BDM/
Non-intrusive
Description
Command Mnemonic
SYNC
Coding Structure
Request a timed reference pulse to determine
target BDC communication speed
Non-intrusive
n/a [1]
D5/d
D6/d
90/d
Enable acknowledge protocol. Refer to NXP
document order no. HCS08RMv1/D.
ACK_ENABLE
ACK_DISABLE
BACKGROUND
Non-intrusive
Non-intrusive
Non-intrusive
Disable acknowledge protocol. Refer to NXP
document order no. HCS08RMv1/D.
Enter ACTIVE BACKGROUND mode if enabled
(ignore if ENBDM bit equals 0)
READ_STATUS
WRITE_CONTROL
READ_BYTE
Non-intrusive
Non-intrusive
Non-intrusive
Non-intrusive
E4/SS
C4/CC
Read BDC status from BDCSCR
Write BDC controls in BDCSCR
Read a byte from target memory
Read a byte and report status
E0/AAAA/d/RD
E1/AAAA/d/SS/RD
READ_BYTE_WS
FXTH87ERM
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Reference manual
Rev. 5.0 — 4 February 2019
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