MC68HC05B6_13 Datasheet, PDF (257/302 Pages) Freescale Semiconductor, Inc – Microcontrollers

H.2
External clock
Preliminary ^{When using an external clock the OSC1 and OSC2 pins should be driven in antiphase (see}
Figure D-2). The t_OXOV or t_ILCH specifications (see Section H.9) do not apply when using an
external clock input. The equivalent specification of the external clock source should be used in
lieu of t_OXOV or t_ILCH.
H.3
RESET pin
When the oscillator is running in a stable condition, the MCU is reset when a logic zero is applied
to the RESET input for a minimum period of 3.0 machine cycles (t_CYC). This differs from the 05B6,
05B4, 705B5, 05B8, 05B16, 705B16 and the 05B32, which require 1.5 t_CYC. For more information
see Section 9.1.3.
Preliminary ^H.4
EPROM
The MC68HC705B32 memory map is given in Figure H-2. The device has a total of 31246 bytes
of EPROM. 14 bytes are used for the reset and interrupt vectors from address $7FF2 to $7FFF.
The main EPROM block of 31232 bytes is located from $0400 to $7DFF. One byte of EPROM is
used as an options register and is located at address $7FDE.
The EPROM array is supplied by the VPP6 pin in both read and program modes. Typically the
user’s software will be loaded into a programming board where V_PP6 is controlled by one of the
bootstrap loader routines. It will then be placed in an application where no programming occurs.
In this case the VPP6 pin should be hardwired to V_DD.
Warning: A minimum V_DD voltage must be applied to the VPP6 pin at all times, including
Preliminary ^{power-on. Failure to do so could result in permanent damage to the device. Unless}
otherwise stated, EPROM programming is guaranteed at ambient (25°C) temperature
only.
14
MC68HC05B6
Rev. 4.1
MC68HC705B32
Freescale
H-7