T89C5115 ATMEL Corporation, T89C5115 Datasheet - Page 80

• Manufacturer Part Number: T89C5115
• Description: Low Pin Count 8-bit MCU with A/D Converter and 16-Kbytes of Flash Memory
• Manufacturer: ATMEL Corporation

Voltage Conversion
Clock Selection
Figure 38. A/D Converter Clock
ADC Standby Mode
80
T89C5115
CPU Core Clock Symbol
CLOCK
CPU
Table 54. Selected Analog Input
When the ADCIN is equals to VAREF the ADC converts the signal to 3FFh (full scale). If
the input voltage equals VAGND, the ADC converts it to 000h. Input voltage between
VAREF and VAGND are a straight-line linear conversion. All other voltages will result in
3FFh if greater than VAREF and 000h if less than VAGND.
Note that ADCIN should not exceed VAREF absolute maximum range! (see section
“AC-DC”)
The ADC clock is the same as CPU.
The maximum clock frequency for ADC is 700 KHz. A prescaler is featured (ADCCLK)
to generate the ADC clock from the oscillator frequency.
When the ADC is not used, it is possible to set it in standby mode by clearing bit ADEN
in ADCON register. In this mode its power dissipation is about 1 uW.
÷
2
SCH2
0
0
0
0
1
1
1
1
Prescaler ADCLK
SCH1
0
0
1
1
0
0
1
1
ADC Clock
SCH0
0
1
0
1
0
1
0
1
Converter
A/D
Selected Analog input
4128A–8051–04/02
AN0
AN1
AN2
AN3
AN4
AN5
AN6
AN7