EM78P458/459
OTP ROM
0 = The Vref of the ADC is connected to Vdd (default value), and the P53/VREF pin carries out the function of P53;
1 = The Vref of the ADC is connected to P53/VREF.
• CE (Bit 6): Control bit used to enable comparator. 0 = Disable comparator
1 = Enable comparator
• COE (Bit 5): Set P57 as the output of the comparator 0 = the comparator acts as an OP if CE=1.
1 = act as a comparator if CE=1.
•IMS2~IMS0 (Bit 4 ~ Bit 2): ADC configuration definition bit.
•CKR1 and CKR0 (Bit 1 and Bit 0): The conversion time select.
00 = Fosc/4;
01 = Fosc/16;
10 = Fsco/64;
11 = The oscillator clock source of ADC is from WDT ring oscillator frequency. ( frequency=256/18ms≒14.2Khz)
1.3 GCON/IOC90
As shown in Fig. 12, OP1 and OP2, the gain amplifiers, are located in the middle of the analog input pins (ADC1 and ADC5) and the
Table 7 Table 7 Shows the Gains and the Operating Range of ADC.
BIT | 7 |
| 6 | 5 |
| 4 |
| 3 | 2 | 1 | 0 | ||
SYMBOL | OP2E |
| OP1E | G22 |
| G21 |
| G20 | G12 | G11 | G10 | ||
*Init_Value | 0 |
| 0 | 0 |
| 0 |
| 0 | 0 | 0 | 0 | ||
Table 8 The Gains and the Operating Range of ADC |
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G10:G12/G20:G22 | Gain |
| Range of Operating Voltage |
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000 |
| 1 |
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| 0 ~ Vref |
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001 |
| 2 |
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| 0 ~ (1/2)Vref |
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010 |
| 4 |
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| 0 ~ (1/4)Vref |
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011 |
| 8 |
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| 0 ~ (1/8)Vref |
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100 |
| 16 |
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| 0 ~ (1/16)Vref |
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101 |
| 32 |
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| 0 ~ (1/32)Vref |
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<Note> Vref can not be less than 3 volts.
2. ADC Data Register (ADDATA/RA)
This specification is subject to change without prior notice. | 33 | 07.01.2003 (V1.3) |