MC68HC05X16 Datasheet, PDF(25/232 Page) Freescale Semiconductor, Inc – High-density complementary metal oxide semiconductor HCMOS) microcontroller unit

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MC68HC05X16 Datasheet, PDF (25/232 Pages) Freescale Semiconductor, Inc – High-density complementary metal oxide semiconductor HCMOS) microcontroller unit

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Freescale Semiconductor, Inc.

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MODES OF OPERATION AND

PIN DESCRIPTIONS

2.1

Modes of operation

The MC68HC05X16 MCU has two modes of operation, single-chip mode and bootstrap mode. In

the MC68HC05X16 the single-chip mode is the normal user operating frequency Table 2-1 shows

the conditions required to enter each mode on the rising edge of RESET.

Table 2-1 Mode of operation selection

MDS

IRQ

TCAP1 TCAP2 PD3 PD4

Mode

VSS AND VSS to VDD VSS to VDD

X

VDD OR

2VDD

VSS

X

X

X Single-chip

0

0 Reserved for Motorola use

Bootstrap mode:

VDD OR

2VDD

VDD

VSS

1

1 Serial RAM loader

VDD OR

2VDD

VDD

VSS

1

0 Jump to RAM + 1

VDD OR

2VDD

VDD

VSS

0

1 Jump to any address

Note:

On the rising edge of RESET, holding the IRQ pin at 2 x VDD is equivalent to holding

the MDS pin at VDD. The device cannot enter single-chip mode unless MDS is tied to

VSS (or left ï¬oating) and IRQ is below VDD.

2.1.1 Single-chip mode

This is the normal user operating mode of the MC68HC05X16. In this mode the device functions

as a self-contained microcomputer (MCU) with all on-board peripherals, including the three 8-bit

I/O ports and the 8-bit input-only port, available to the user. All address and data activity occurs

within the MCU.

MC68HC05X16 MODES OF OPERATION AND PIN DESCRIPTIONS

For More Information On This Product,

2-1

Go to: www.freescale.com

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