UPD78F9418A NEC, UPD78F9418A Datasheet - Page 148

• Manufacturer Part Number: UPD78F9418A
• Description: (UPD7894xxA) 8-Bit Single Chip Microcontrollers
• Manufacturer: NEC

www.DataSheet4U.com
10.4.3 Operation mode of 8-bit A/D converter
to select an analog input channel from ANI0 to ANI6 for A/D conversion.
request signal (INTAD0) is generated.
148
The 8-bit A/D converter is initially in the select mode. In this mode, A/D input selection register 0 (ADS0) is used
A/D conversion can be started only by software, that is, by setting A/D converter mode register 0 (ADM0).
The A/D conversion result is saved to A/D conversion result register 0 (ADCR0). At the same time, an interrupt
• • • • Software-started A/D conversion
Remarks 1. n = 0, 1, ..., 6
A/D conversion
Setting bit 7 (ADCS0) of A/D converter mode register 0 (ADM0) triggers A/D conversion for a voltage applied to
the analog input pin specified in A/D input selection register 0 (ADS0). Upon completion of A/D conversion,
the conversion result is saved to A/D conversion result register 0 (ADCR0). At the same time, an interrupt
request signal (INTAD0) is generated. Once A/D conversion is activated, and completed, another session of
A/D conversion is started. A/D conversion is repeated until new data is written to ADM0. If data where the
ADCS0 bit is 1 is written to ADM0 again during A/D conversion, the current session of A/D conversion is
discontinued, and a new session of A/D conversion begins for the new data. If data where the ADCS0 bit is 0
is written to ADM0 again during A/D conversion, A/D conversion is stopped immediately.
INTAD0
ADCR0
2. m = 0, 1, ..., 6
Rewriting ADM0
ADCS0 = 1
Figure 10-6. Software-Started A/D Conversion
ANIn
User’s Manual U13952EJ3V0UD
ANIn
ANIn
Rewriting ADM0
ADCS0 = 1
Conversion is
discontinued;
no conversion
result is preserved.
ANIn
ANIn
ANIm
ANIm
ADCS0 = 0
ANIm
Stop