UPD75238GJ NEC [NEC], UPD75238GJ Datasheet - Page 114

• Manufacturer Part Number: UPD75238GJ
• Description: 4 BIT SINGLE-CHIP MICROCOMPUTER
• Manufacturer: NEC [NEC]

114
(2) Pins of the A/D converter
(3) A/D conversion mode register
(a) AN0 to AN7
(b) AV
(c) AV
The A/D conversion mode register (ADM) is an 8-bit register used to select analog input channels, direct
the start of conversion, and detect the completion of conversion. (See Fig. 4-63.)
ADM is set with an 8-bit manipulation instruction. The conversion completion detection flag (EOC) in bit
2 and the conversion start direction bit (SOC) in bit 3 can be manipulated individually.
A RESET input initializes ADM to 04H. That is, only EOC is set to 1, with all bits cleared to 0.
AN0 to AN7 are the input pins for eight analog signal channels. Analog signals subject to A/D
conversion are applied to these pins.
The A/D converter contains a sample-and-hold circuit, and analog input voltages are internally
maintained during A/D conversion.
A reference voltage for the A/D converter is applied to these pins.
By using an applied voltage across AV
digital signals.
AV
This is the supply voltage pin for the A/D converter. When the A/D converter is not used or is in the
standby mode, the potential of the AV
REF
SS
DD
, AV
must be always V
SS
SS
.
REF
DD
pin must be equal to that of the V
and AV
SS
, signals applied to AN0 to AN7 are converted to
DD
pin.
PD75238