M32CSLASH8A datasheet(364/372 Pages) RENESAS

364 / 372 page

M32C/8A Group

24. Usage Notes

Rev.1.00

Jul 15, 2007

Page 347 of 352

REJ09B0385-0100

24.10 A/D Converter

• Set the ADST bit to 1 (A/D conversion starts) after setting registers AD0CON0 (ADST bit excluded),

AD0CON1, AD0CON2, AD0CON3, and AD0CON4.

• When the VCUT bit in the AD0CON1 register is changed from 0 (VREF not connected) to 1 (VREF

connected), wait for 1

μs or more to start A/D conversion.

Set the VCUT bit to 0 when A/D conversion is not used to reduce power consumption.

• To prevent latch-up and malfunction due to noise and also to minimize a conversion error, insert a capacitor

between the AVSS pin and each of the following pins: the AVCC pin, VREF pin, or analog input pin ANi_j

(i = none, 15; j = 0 to 7). Insert a capacitor between the VCC pin and the VSS pin as well. Figure 24.4 shows

an example of individual pin handling.

Figure 24.4

Individual Pin Handling

• Set the port direction bit in the PDk register (k = 0 to 15), which corresponds to a pin used as an analog input

pin, to 0 (input mode). Also, set the port direction bit in the PDk register corresponding to the ADTRG pin, to

0 (input mode.)

• When the key input interrupt is used, do not select pins P10_4 to P10_7 (AN_4 to AN_7) as analog input pins.

• φAD frequency must be 16 MHz or lower when VCC1 = 4.2 V to 5.5 V, or 10 MHz or lower when

VCC1 = 3.0 V to 5.5 V. When the sample and hold is not activated,

φAD frequency must be 250 kHz or

higher. When the sample and hold is activated,

φAD frequency must be 1 MHz or higher.

• When A/D operating mode is changed, set bits CH2 to CH0 in the AD0CON0 register or bits SCAN1 and

SCAN0 in the AD0CON1 register again to select analog input pins.

• The voltage applied to AN_0 to AN_7, AN15_0 to AN15_7, ANEX0, and ANEX1 must be VCC1 or below.

VCC1

VSS

AVCC

AVSS

VREF

ANi

MCU

NOTES:

1.C1

≥ 0.47

μF, C2 ≥ 0.47 μF, C3 ≥ 10000 pF, C4 ≥ 0.1 μF, C5 ≥ 0.1 μF (reference values)

2.Use thick and shortest possible wiring to connect capacitors.

VCC2

VSS

VCC1

VCC2

VCC1

M32C/8A Datasheet(PDF) 364 Page - Renesas Technology Corp

M32C/8A Datasheet(HTML) 364 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL