S9S08QD4CSC View Datasheet(PDF) - Freescale Semiconductor

Part Name

Description

Manufacturer

S9S08QD4CSC

8-BIT HCS08 Microcontrollers

Freescale Semiconductor 

Development Support

BDC CLOCK

(TARGET MCU)

HOST DRIVE

TO BKGD PIN

HIGH-IMPEDANCE

TARGET MCU

DRIVE AND

SPEED-UP PULSE

PERCEIVED START

OF BIT TIME

SPEEDUP

PULSE

BKGD PIN

10 CYCLES

10 CYCLES

EARLIEST START

OF NEXT BIT

HOST SAMPLES BKGD PIN

Figure 12-4. BDM Target-to-Host Serial Bit Timing (Logic 0)

12.2.3 BDC Commands

BDC commands are sent serially from a host computer to the BKGD 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 12-1 shows all HCS08 BDC commands, a shorthand description of their coding structure, and the

meaning of each command.

Coding Structure Nomenclature

This nomenclature is used in Table 12-1 to describe the coding structure of the BDC commands.

MC9S08QD4 Series MCU Data Sheet, Rev. 6

164

Freescale Semiconductor

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