MC812A4CPVE8 Freescale Semiconductor, MC812A4CPVE8 Datasheet - Page 208

• Manufacturer Part Number: MC812A4CPVE8
• Description: IC MCU 16BIT EEPROM 4K 112-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC12r

Specifications of MC812A4CPVE8

• Core Processor: CPU12
• Core Size: 16-Bit
• Speed: 8MHz
• Connectivity: SCI, SPI
• Peripherals: POR, WDT
• Number Of I /o: 83
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: EEPROM
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 112-LQFP
• Processor Series: HC812A
• Core: HC12
• Data Bus Width: 16 bit
• Data Ram Size: 1 KB
• Interface Type: SCI, SPI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 91
• Number Of Timers: 8
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit, 8 Channel
• Controller Family/series: 68HC12
• No. Of I/o's: 91
• Eeprom Memory Size: 4KB
• Ram Memory Size: 1KB
• Cpu Speed: 8MHz
• No. Of Timers: 1
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

Analog-to-Digital Converter (ATD)
16.11 Using the ATD to Measure a Potentiometer Signal
This exercise allows the student to utilize the ATD on the HC12 to measure a potentiometer signal output
routed from the UDLP1 board to the HC12 ATD pin PAD6. First the ATDCTL registers are initialized. A
delay loop of 100 µs is then executed. The resolution is set up followed by a conversion set up on
channel 6. After waiting for the status bit to set, the result goes to the D accumulator. If the program is
working properly, a different value should be found in the D accumulator as the left potentiometer is varied
for each execution of the program.
16.11.1 Equipment
For this exercise, use the M68HC812A4EVB emulation board.
16.11.2 Code Listing
; ----------------------------------------------------------------------
;
; ----------------------------------------------------------------------
;
MAIN:
DONE:
; ----------------------------------------------
;
; ----------------------------------------------
INIT:
208
ORG
BSR
BSR
BRA
LDAA
STAA
BSR
LDAA
STAA
LDAA
STAA
RTS
A comment line is delimited by a semicolon. If there is no code before
comment, a semicolon(;) must be placed in the first column to avoid
assembly errors.
MAIN PROGRAM
Subroutine INIT: Initialize ATD
$7000
INIT
CONVERT
DONE
#$80
ATDCTL2
DELAY
#$00
ATDCTL3
#$01
ATDCTL4
MC68HC812A4 Data Sheet, Rev. 7
; 16K On-Board RAM, User code data area,
; Branch to INIT subroutine to Initialize ATD
; Branch to CONVERT Subroutine for conversion
; Branch to Self, Convenient place for breakpoint
; Allow ATD to function normally,
; ATD Flags clear normally & disable interrupts
; Delay (100 uS) for WAIT delay time.
; Select continue conversion in BGND Mode
; Ignore FREEZE in ATDCTL3
; Select Final Sample time = 2 A/D clocks
; Prescaler = Div by 4 (PRS4:0 = 1)
; Return from subroutine
start main program at $7000
NOTE
;
Freescale Semiconductor