cop8cfe9 National Semiconductor Corporation, cop8cfe9 Datasheet - Page 33

• Manufacturer Part Number: cop8cfe9
• Description: 8-bit Cmos Flash Microcontroller With 8k Memory, Virtual Eeprom, And 10-bit A/d
• Manufacturer: National Semiconductor Corporation

7.0 Power Saving Features
8.0 A/D Converter
This device contains a 16-channel, multiplexed input, suc-
cessive approximation, 10 bit Analog-to-Digital Converter.
Pins AV
8.1 OPERATING MODES
It supports both Single Ended and Differential modes of
operation.
Two specific analog channel selection modes are supported.
These are as follows:
1. Allow any specific channel to be selected at one time.
2. Allow any differential channel pair to be selected at one
In both Single Ended and Differential modes, there is the
capability to connect the analog multiplexor output and A/D
The A/D Converter performs the specific conversion re-
quested and stops.
time. The A/D Converter performs the specific differen-
tial conversion requested and stops.
CC
and AGND are used for the voltage reference.
FIGURE 19. Multi-Input Wake-Up Logic
(Continued)
33
converter input to external pins. This provides the ability to
externally connect a common filter/signal conditioning circuit
for the A/D Converter.
The A/D Converter is supported by three memory mapped
registers: two result registers and the control register. When
the device is reset, the mode control register (ENAD) is
cleared, the A/D is powered down and the A/D result regis-
ters have unknown data.
8.1.1 A/D Control Register
The control register, ENAD, contains 4 bits for channel se-
lection, 1 bit for mode selection, 1 bit for the multiplexor
output selection, 1 bit for prescaler selection, and a Busy bit.
An A/D conversion is initiated by setting the ADBSY bit in the
ENAD control register. The result of the conversion is avail-
able to the user in the A/D result registers, ADRSTH and
ADRSTL, when ADBSY is cleared by the hardware on
completion of the conversion.
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