HC05 datasheet(32/232 Pages) MOTOROLA

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MOTOROLA

2-8

MC68HC05X16

Rev. 1

MODES OF OPERATION AND PIN DESCRIPTIONS

The following list summarizes the effect of WAIT mode on the modules of the MC68HC05X16.

–

The watchdog timer functions according to the mask option selected; see

Section 10.1.4.2

–

The EEPROM is not affected; see Section 3.7

–

The SCI is not affected; see Section 7.14

–

The timer is not affected; see Section 6.7

–

The PLM is not affected; see Section 8.4

–

The A/D converter is not affected; see Section 9.4

–

The I-bit in the CCR is cleared

–

The MCAN module is unaffected

2.2.2.1

Power consumption during WAIT mode

Power consumption during WAIT mode depends on how many systems are active. The power

consumption will be highest when all the systems (A/D, timer, EEPROM, SCI and MCAN) are

active, and lowest when the EEPROM erase and programming mechanism, SCI and A/D are

disabled and the MCAN is in SLEEP mode. The timer cannot be disabled in WAIT mode. It is

important that before entering WAIT mode, the programmer sets the relevant control bits for the

individual modules to reﬂect the desired functionality during WAIT mode.

Power consumption may be further reduced by the use of SLOW mode. (See Section 2.2.3).

2.2.3

SLOW mode

The SLOW mode function is controlled by the SM bit in the miscellaneous register at location

$000C. It allows the user to insert, under software control, an extra divide-by-16 between the

oscillator and the internal clock driver (see Figure 2-5). This feature allows all the internal

operations to slow down and thus reduces power consumption.

Warning: The SLOW mode function should not be enabled while using the A/D converter or while

erasing/programming the EEPROM unless the internal A/D RC oscillator is turned on.

HC05 Datasheet(PDF) 32 Page - Motorola, Inc