gc80c520a CORERIVER Semiconductor, gc80c520a Datasheet - Page 63

• Manufacturer Part Number: gc80c520a
• Description: Midas1.0 Family Mask Rom/eprom/romless 8-bit Turbo Microcontrollers
• Manufacturer: CORERIVER Semiconductor

Each conversion time for each system clock frequency is presented in Table 6-11.
6.2.7.3 INTERNAL A/D CONVERSION PROCEDURE
The following sequences is the way to execute ADC conversion as described in Figure 6-31.
(Vdd=5V/3V)
(Vdd=5V)
20 MHz
10 MHz
1. Analog input voltage must be in the voltage range between V
2. Configure the analog input pins to analog input mode by setting the bits of ADCSEL[3:0] to 1.
3. Switch off a pull-up resistor by setting P0SEL[0] or P1SEL[3:1] to 1.
4. Before the conversion starts, you must select one of the four input pins (ADC0–ADC3) by setting
5. To enable A/D conversion, set ADCON[7] to 1.
6. To start A/D conversion, set ADCON[6] to 1.
7. When the conversion is completed, the AD_END will be set to 0 and ADCF flag to “1”.
8. Check AD_END or ADCF flag to verify if the conversion is finished or not.
9. The converted digital value is loaded to the ADC result register, ADCR[7:0] and ADCON[0]. Then
10. The A/D conversion result can now be read from the ADCR and ADCON register.
OSC
ADCON[3:2] to the appropriate value.
the ADC enters an idle state.
MiDAS1.0 Family
Divide (ADCSEL[7:5])
000 (OSC/2)
001 (OSC/4)
010 (OSC/8)
011 (OSC/16)
100 (OSC/32)
000 (OSC/2)
001 (OSC/4)
010 (OSC/8)
011 (OSC/16)
100 (OSC/32)
Table 6-11 Example of conversion time vs. clock frequency
312.5 KHz
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1.25 MHz
1.25 MHz
625 KHz
625 KHz
2.5 MHz
2.5 MHz
10 MHz
5 MHz
5 MHz
F
ADC
T (1/F
100 ns
200 ns
400 ns
800 ns
200 ns
400 ns
800 ns
1.6 us
1.6 us
3.2 us
ADC
SS
)
and V
1 sample conversion time
DD.
140.8 us
140.8 us
281.6 us
17.6 us
35.2 us
70.4 us
17.6 us
35.2 us
70.4 us
8.8 us