R8CSLASH15 datasheet(180/277 Pages) RENESAS

180 / 277 page

R8C/14 Group, R8C/15 Group

16. A/D Converter

Rev.2.10

Jan 19, 2006

Page 168 of 253

REJ09B0164-0210

16. A/D Converter

The A/D converter consists of one 10-bit successive approximation A/D converter circuit with a capacitive

coupling amplifier. The analog input shares the pins with P1_0 to P1_3. Therefore, when using these pins,

ensure the corresponding port direction bits are set to “0” (input mode).

When not using the A/D converter, set the VCUT bit in the ADCON1 register to “0” (Vref unconnected), so

that no current will flow from the VREF pin into the resistor ladder, helping to reduce the power consumption

of the chip.

The result of A/D conversion is stored in the AD register.

Table 16.1 lists the Performance of A/D converter. Figure 16.1 shows the Block Diagram of A/D Converter.

Figures 16.2 and 16.3 show the A/D converter-related registers.

NOTES:

1. Analog input voltage does not depend on use of sample and hold function.

2. The frequency of

φAD must be 10 MHz or below.

Without sample and hold function, the

φAD frequency should be 250 kHz or above.

With the sample and hold function, the

φAD frequency should be 1 MHz or above.

3. In repeat mode, only 8-bit mode can be used.

Table 16.1

Performance of A/D converter

Item

Performance

A/D Conversion Method

Successive approximation (with capacitive coupling amplifier)

Analog Input Voltage(1)

0V to Vref

Operating Clock

φAD(2)

4.2V

≤ AVCC ≤ 5.5V f1, f2, f4

2.7V

≤ AVCC < 4.2V f2, f4

Resolution

8 bit or 10 bit is selectable

Absolute Accuracy

AVCC = Vref = 5V

• 8-bit resolution ±2 LSB

• 10-bit resolution ±3 LSB

AVCC = Vref = 3.3 V

• 8-bit resolution ±2 LSB

• 10-bit resolution ±5 LSB

Operating Mode

One-shot and repeat modes(3)

Analog Input Pin

4 pins (AN8 to AN11)

A/D Conversion Start Condition • Software trigger

Set the ADST bit in the ADCON0 register to “1” (A/D conversion

starts)

•Capture

Timer Z interrupt request is generated while the ADST bit is set to “1”

Conversion Rate Per Pin

• Without sample and hold function

8-bit resolution: 49

φAD cycles, 10-bit resolution: 59φAD cycles

• With sample and hold function

8-bit resolution: 28

φAD cycles, 10-bit resolution: 33φAD cycles

R8C/15 Datasheet(PDF) 180 Page - Renesas Technology Corp

R8C/15 Datasheet(HTML) 180 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