Rainbow Electronics T89C51AC2 - Manual (Page 81)

81
T89C51AC2
Rev. B – 19-Dec-01
Figure 36. ADC Description
Figure 37 shows the timing diagram of a complete conversion. For simplicity, the figure
depicts the waveforms in idealized form and do not provide precise timing information.
For ADC characteristics and timing parameters refer to the Section “AC Characteristics”
of the T89C51AC2 datasheet.
Figure 37. Timing Diagram
Note: Tsetup min = 4 us
Tconv=11 clock ADC = 1sample and hold + 10 bit conversion
The user must ensure that 4 us minimum time between setting ADEN and the start of the
first conversion.
AN0/P1.0
AN1/P1.1
AN2/P1.2
AN3/P1.3
AN4/P1.4
AN5/P1.5
AN6/P1.6
AN7/P1.7
000
001
010
011
100
101
110
111
SCH2
ADCON.2
SCH0
ADCON.0
SCH1
ADCON.1
ADC
CLOCK
ADEN
ADCON.5
ADSST
ADCON.3
ADEOC
ADCON.4 ADC
Interrupt
Request
EADC
IEN1.1
CONTROL
AVSS
Sample and Hold
ADDH
VAREF
R/2R DAC
VAGND
8
10
+
-
ADDL 2 SAR
ADCIN
ADEN
ADSST
ADEOC
T
SETUP
T
CONV
CLK