M32CSLASH8A datasheet(289/372 Pages) RENESAS

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M32C/8A Group

19. D/A Converter

Rev.1.00

Jul 15, 2007

Page 272 of 352

REJ09B0385-0100

19. D/A Converter

The D/A converter consists of two independent 8-bit R-2R ladder D/A converter circuits.

Digital code is converted to an analog voltage every time a value to be converted is written to the corresponding DAi

The DAiE bit in the DACON register determines whether the D/A conversion result is output or not. When the DAiE

bit is set to 1 (input enabled), the corresponding port cannot be pulled up.

When the D/A converter is not used, set the DAi register to 00h and the DAiE bit to 0 (output disabled).

Output analog voltage (

V) is obtained from the value n (n = decimal) set in the DAi register.

VREF: Reference voltage (VREF remains connected even if the VCUT bit in the AD0CON1 register is set to 0)

Table 19.1 lists specifications of the D/A converter. Figure 19.1 shows a block diagram of the D/A converter. Table

19.2 lists pin settings of DA0 and DA1. Figure 19.2 shows registers associated with the D/A converter. Figure 19.3

shows a D/A converter equivalent circuit.

Table 19.1

D/A Converter Specifications

Figure 19.1

D/A Converter Block Diagram

Table 19.2

Pin Settings

NOTES:

1. Set the PS3 register after setting other registers.

2. Set the PD9 or PS3 register immediately after the PRC2 bit in the PRCR register is set to 1 (write enable). Do

not generate an interrupt or a DMA or DMACII transfer between these two instructions.

Item

Specification

D/A conversion method

R-2R

Resolution

8 bits

Analog output pin

2 channels

Port

Function

Bit Setting

PD9 Register(2)

PSL3 Register

PS3 Register(1)(2)

P9_3

DA0 output

PD9_3=0

PSL3_3=1

PS3_3=0

P9_4

DA1 output

PD9_4=0

PSL3_4=1

PS3_4=0

V =

256

VREF x n

(n = 0 to 255)

DA0E, DA1E: Bits in the DACON register

Low-order bits of data bus

R-2R Resistor Ladder

DA1 Register

R-2R Resistor Ladder

DA0E

DA1E

DA1

DA0

DA0 Register

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