MC68HC908LB8_05 Datasheet, PDF (54/234 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Op Amp/Comparator Module
M68HC08 CPU
CPU
REGISTERS
ARITHMETIC/LOGIC
UNIT (ALU)
CONTROL AND STATUS
REGISTERS — 64 BYTES
USER FLASH — 8 KBYTES
USER RAM — 128 BYTES
INTERNAL BUS
DUAL CHANNEL PWM
MODULE
HIGH RESOLUTION PWM
MODULE
LOW-VOLTAGE INHIBIT
MODULE
PTA6⁽¹⁾/AD5/TCH0/KBI6
PTA5⁽¹⁾/RST/KBI5
PTA4⁽¹⁾/AD4/KBI4
PTA3⁽¹⁾/AD3/KBI3
PTA2⁽¹⁾/AD2/KBI2
PTA1⁽¹⁾/AD1/KBI1
PTA0⁽¹⁾/AD0/KBI0
MONITOR ROM — 350 BYTES
FLASH PROGRAMMING
ROUTINES ROM — 674 BYTES
USER FLASH VECTOR SPACE — 34 BYTES
OSCILLATOR
MODULE
COMPUTER OPERATING
PROPERLY MODULE
2-CHANNEL TIMER
MODULE
8-BIT ANALOG-TO-DIGITAL
CONVERTER MODULE
PTB7/V_OUT/AD6/FAULT⁽²⁾
PTB6/V–
PTB5/V+
PTB4/PWM1
PTB3/PWM0
PTB2/FAULT⁽²⁾
PTB1/BOT
PTB0/TOP
SYSTEM INTEGRATION
MODULE
KEYBOARD INTERRUPT
MODULE
PTC2⁽¹⁾/SHTDWN/IRQ
PTC1⁽¹⁾/OSC2
PTC0⁽¹⁾/OSC1
V_DD
POWER
V_SS
OP AMP/COMPARATOR
MODULE
Notes:
1. Pin contains integrated pullup device.
2. Fault function switchable between pins PTB2 and PTB7.
Figure 4-1. Block Diagram Highlighting Op Amp/Comparator Block and Pins
4.4 Functional Description
The op amp/comparator module has two modes of operation — op amp mode and comparator mode. Op
amp mode optimizes the module for accurate signal amplification with low input offset voltage.
Comparator mode optimizes the module for use as a comparator with fast output response.
The output of the op amp/comparator shares its pin with an analog-to-digital converter (ADC6) channel.
The fault function of the PWM can also be switched to share this pin. The ADC channel function and the
op amp output can be enabled simultaneously so that the output of the op amp could be sampled directly
by the associated ADC channels. See Figure 4-2.
NOTE
Setting an op amp/comparator enable control bit (OACE) and an op
amp/comparator module selected control bit (OACM) forces V+ and V– to
be inputs and V_OUT to be an output, overriding the data direction register.
MC68HC908LB8 Data Sheet, Rev. 1
54
Freescale Semiconductor