Version 2.1
RA8906
8-Bit Micro-Controller
Block Diagram
80Byte
8-Bit
e-RISC
e-MCU
CPU Core
Core
XCLKI
XCLKQ
RESET#
SRAM
64KByte
Flash ROM
User
Registers
OSC.
ISP/ISD
Control
Logic
Time-Base
Timer x 3
System
Registers
DAC 1
DAC 2
User I/O x 8
User I/O x 8
Watch-Dog
DACO1
DACO2
MONITOR#
BREAK#
RXD
TXD
System
Interface
RS-232
Interface
PT1_[7:0]
PT2_[7:0]
Pin Description
Signal
RESET#
BREAK#
MONITOR#
I/O
IN
IN
IN
Description
External Hardware Reset, active low.
This pin is used to reset the system.
User Program Break, active low.
This signal is used to break the user’s
program from the ISD mode.
Monitor Program Select, active low.
This signal is used to select the system
boot from monitor program(ROM) or user program(Flash). This signal has to pull
low when user wants to download the data from PC or enter the ISP/ISD mode.
8-bit I/O of Port 1.
These signals are used as general-purpose I/O port.
PT1_[7:0] provide 8mA driving current.
8-bit I/O of Port 2.
These signals are used as general-purpose I/O port.
PT2_[7:2] provide 4mA driving current. PT2_[1:0] provide 16mA driving current.
DAC1/2 Current Output.
In the DAC mode, this pin is the current output of
DAC1 and DAC2. In the PWM mode, this pin is the output of PWM.
Receive Data.
This is the received data input of UART. Normally it’s connected
to the RS232’s TX of PC.
Transmit Data.
This signal is the transmitted data output of UART. Normally it’s
connected to the RS232’s RX of PC.
Oscillator Input.
This is the input signal of internal oscillator.
Oscillator Output.
This is the output signal of internal oscillator.
Address Bus.
These pins are used for external system ROM address. Normally,
users will not use these pins.
PT1_[7:0]
PT2_[7:0]
DACO1
DACO2
RXD
TXD
XCLKI
XCLKQ
A[11:0]
I/O
I/O
OUT
IN
OUT
IN
OUT
OUT
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RAIO [ RAIO TECHNOLOGY INC. ]
