M32C8A Datasheet, PDF (289/372 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M32C/80 Series

M32C/8A Group
19. D/A Converter
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
register (i = 0, 1).
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.
V=
VREF x n
256
(n = 0 to 255)
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
Item
D/A conversion method
R-2R
Resolution
8 bits
Analog output pin
2 channels
Specification
Low-order bits of data bus
DA0 Register
R-2R Resistor Ladder
DA0E 0
DA0
1
DA1 Register
R-2R Resistor Ladder
DA1E 0
DA1
1
DA0E, DA1E: Bits in the DACON register
Figure 19.1 D/A Converter Block Diagram
Table 19.2 Pin Settings
Bit Setting
Port
Function
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
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.
Rev.1.00 Jul 15, 2007 Page 272 of 352
REJ09B0385-0100