Datasheet

MC68HC08JT8
Technical Data MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
278 MC68HC08JT8 Freescale Semiconductor
B.2 Introduction
This section introduces the MC68HC08JT8, a low-voltage ROM part
version to the MC68HC908JB8. The entire data book apply to this ROM
device, with exceptions outlined in this appendix.
B.3 MCU Block Diagram
Figure B-1 shows the block diagram of the MC68HC08JT8.
B.4 Memory Map
The MC68HC08JT8 has 8,192 bytes of user ROM from $DC00 to
$FBFF, and 16 bytes of user ROM vectors from $FFF0 to $FFFF. On the
MC68HC908JB8, these memory locations are FLASH memory.
Figure B-2 shows the memory map of the MC68HC08JT8.
Table B-1. Summary of MC68HC08JT8 and MC68HC908JB8 Differences
MC68HC08JT8 MC68HC908JB8
Memory ($DC00–$FBFF) 8,192 bytes ROM 8,192 bytes FLASH
User vectors ($FFF0–$FFFF) 16 bytes ROM 16 bytes FLASH
Registers at $FE08 and $FF09
Not used;
locations are reserved
FLASH related registers.
$FE08 — FLCR
$FF09 — FLBPR
Bit 4 at CONFIG ($001F)
Not used;
bit is reserved.
LVID: low-voltage inhibit
disable bit
Monitor ROM
($FC00–$FDFF and $FE10–$FFDF)
$FC00–$FDFF: Not used.
$FE10–$FFDF: Used for
testing purposes only.
Used for testing and FLASH
programming/erasing.
Low voltage inhibit module Not available (disabled) Available
Universal Serial Bus (USB) module
Not available. User should set
the SUSPND bit to logic 1 to
reduce power consumption.
Available
On-chip 3.3V regulator Not available (disabled) Available
Operating voltage 2.0 to 3.6V 4.0 to 5.5V
Operating frequency
f
OPMAX
= 2.5MHz at 2V
f
OPMAX
= 3MHz at 3V
3MHz