PIRA32 Microcontroller
m32.pdf - page 4
© 2016 Pira.cz
V
DD
Positive supply
Apply V
DD
power supply voltage to this pin.
Decoupling capacitor is required on V
DD
and V
SS
pins. A 100 nF 10-50V
ceramic capacitor is recommended. The decoupling capacitor should be
placed as close to the pins as possible.
V
SS
Ground reference
All V
SS
pins must be connected.
OSC IN
Crystal oscillator input
Tie to 4.332 MHz crystal pin.
OSC OUT
Crystal oscillator output
Tie to 4.332 MHz crystal pin.
Can be used for clocking another device on the board.
LED1
Operation LED
Connect an indication LED (+) through a resistor or leave unconnected.
LED2
Pilot LED
Connect an indication LED (+) through a resistor or leave unconnected.
SCL
I
2
C serial clock output
Open-drain terminal, external 2k pull-up resistor is required.
SDA
I
2
C serial data input/output
Open-drain terminal, external 2k pull-up resistor is required.
TXD
Serial port transmit data
Serial RS-232 port transmit data output (software selectable 1200 to 19200
bps). Logical high = idle.
This pin is required for proper software configuration of the device.
RXD
Serial port receive data
Serial RS-232 port receive data input (software selectable 1200 to 19200
bps). Logical high = idle.
This pin is required for proper software configuration of the device.
DA0-DA7
D/A Converter bit 0 to 7
These pins together form driving signal for parallel D/A converter. A simple
low-cost R/2R resistor network can serve the D/A converter function. The R
value should be 1k.
All pins marked as “reserved” should be left unconnected or tied to V
DD
through a 10k resistor.
