MC68HC05T16 Datasheet, PDF (90/128 Pages) Motorola, Inc – High-density complementary metal oxide semiconductor (HCMOS) microcontroller unit

10.1
ADC Inputs
The ADC has two input channels: one dedicated input pin at ADCIN0 and one shared pin at
PF4/ADCIN1.
10.1.1 PF4/ADCIN1
ADCIN1 multiplexes with PF4 at this pin. When the ADC1 bit of Port F Configuration register is
cleared, PF4/ADCIN1 is configured for PF4 and follows Port F DDR assignment. When ADC1 bit
is set, PF4 is configured as ADCIN1 analog input, and Port F DDR has no effect on this pin.
Reading PF4 when configured as an ADC input is zero.
10.1.2 ADCIN0
ADCIN0 is a dedicated analog input channel.
10.2
Program Example
10
The following example shows how to convert analog input channel 0 (ADCIN0). For ADCIN1
conversion, change #$00 to #$20. ADCSR is the ADC Control/Status register.
LDA #$00
STA ADCSR
;ADC Control and Status Register
DTA BRSET 7, ADCSR, ATD
INC ADCSR
LDA ADCSR
AND #$1F
CMP #$1F
BLS DTA
;out of range
ATD ... ;analog value in ADC.
;ANALOG IN = ([AD4:0] +1)*0.15625V at Vdd = 5V
MOTOROLA
10-2
ANALOG TO DIGITAL CONVERTER
TPG
MC68HC05T16