ADUC814 Analog Devices, ADUC814 Datasheet - Page 47

• Manufacturer Part Number: ADUC814
• Description: Precision Analog Microcontroller: 1.3MIPS 8052 MCU + 8kB Flash + 6-Ch 12-Bit ADC + Dual 12-Bit DAC
• Manufacturer: Analog Devices

Specifications of ADUC814

• Mcu Core: 8052
• Mcu Speed (mips): 1.3
• Sram (bytes): 256Bytes
• Gpio Pins: 17
• Adc # Channels: 6

8051 COMPATIBLE ON-CHIP PERIPHERALS
This section gives a brief overview of the various secondary
peripheral circuits that are available to the user on-chip. These
functions are fully 8051 compatible and are controlled via
standard 8051 SFR bit definitions.
Parallel I/O Ports 1 and 3
The ADuC814 has two input/output ports. In addition to per-
forming general-purpose I/O, some ports are multiplexed with
an alternate function for the peripheral features on the device.
In general, when a peripheral is enabled, that pin may not be
used as a general purpose I/O pin.
Port 1 is an 8-bit port directly controlled via the P1 SFR (SFR
address = 90H). The Port 1 pins are divided into two distinct
pin groupings.
P1.0 and P1.1 pins on Port 1 are bidirectional digital I/O pins
with internal pull-ups. If P1.0 and P1.1 have 1s written to them
via the P1 SFR, these pins are pulled high by the internal pull-
up resistors. In this state they can also be used as inputs. As
input pins being externally pulled low, they source current
because of the internal pull-ups. With 0s written to them, both
of these pins drive a logic low output voltage (VOL) and are
capable of sinking 10 mA compared to the standard 1.6 mA
sink capability on the other port pins. These pins also have
various secondary functions described in Table 20.
Table 20. Port 1, Alternate Pin Functions
Pin No.
P1.0
P1.1
The remaining Port 1 pins (P1.2–P1.7) can be configured only
as analog input (ADC), analog output (DAC) or digital input
Alternate Function
T2 (Timer/Counter 2 External Input)
T2EX (Timer/Counter 2 Capture/Reload Trigger)
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pins. By default (power-on) these pins are configured as analog
inputs, that is, 1 written in the corresponding Port 1 register bit.
To configure any of these pins as digital inputs, the user should
write a 0 to these port bits to configure the corresponding pin as
a high impedance digital input.
Port 3 is a bidirectional port with internal pull-ups directly con-
trolled via the P3 SFR (SFR address = B0H). Port 3 pins that
have 1s written to them are pulled high by the internal pull-ups
and in that state, they can be used as inputs. As inputs, Port 3
pins being pulled externally low sources current because of the
internal pull-ups. Port 3 pins also have various secondary
functions described in Table 21.
Table 21. Port 3, Alternate Pin Functions
Pin No.
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
Additional Digital Outputs Pins
Pins P1.0 and P1.1 can be used to provide high current (10 mA
sink) general-purpose I/O.
Alternate Function
RxD (UART Input Pin)
(or Serial Data I/O in Mode 0)
TxD (UART Output Pin)
(or Serial Clock Output in Mode 0)
INT0 (External Interrupt 0)
INT1 (External Interrupt 1)
T0 (Timer/Counter 0 External Input)
T1 (Timer/Counter 1 External Input)
SS (Slave Select in SPI Slave Mode)
MISO (Master in Slave Out in SPI Mode)
MOSI (Master Out Slave In in SPI Mode)
ADuC814