R8C/1A Group, R8C/1B Group
18. Flash Memory
Rev.1.30
Dec 08, 2006
Page 269 of 315
REJ09B0252-0130
18.5
Standard Serial I/O Mode
In standard serial I/O mode, the user ROM area can be rewritten while the MCU is mounted on-board by using a
serial programmer which is suitable for the MCU.
Standard serial I/O mode is used to connect with a serial programmer using a special clock asynchronous serial I/O.
There are three standard serial I/O modes:
•
Standard serial I/O mode 1 ................ Clock synchronous serial I/O used to connect with a serial programmer
•
Standard serial I/O mode 2 ................ Clock asynchronous serial I/O used to connect with a serial programmer
•
Standard serial I/O mode 3 ................ Special clock asynchronous serial I/O used to connect with a serial
programmer
This MCU uses standard serial I/O mode 2 and standard serial I/O mode 3.
Refer to
Appendix 2. Connection Examples between Serial Writer and On-Chip Debugging Emulator.
Contact the manufacturer of your serial programmer for additional information. Refer to the user’s manual of your
serial programmer for details on how to use it.
Table 18.7 lists the Pin Functions (Flash Memory Standard Serial I/O Mode 2), Table 18.8 lists the Pin Functions
(Flash Memory Standard Serial I/O Mode 3). Figure 18.17 shows Pin Connections for Standard Serial I/O Mode 3.
After processing the pins shown in Table 18.8 and rewriting the flash memory using a programmer, apply “H” to
the MODE pin and reset the hardware to run a program in the flash memory in single-chip mode.
18.5.1
ID Code Check Function
The ID code check function determines whether the ID codes sent from the serial programmer and those written
in the flash memory match (refer to
18.3 Functions to Prevent Rewriting of Flash Memory
).
Table 18.7
Pin Functions (Flash Memory Standard Serial I/O Mode 2)
Pin
Name
I/O
Description
VCC,VSS
Power input
Apply the voltage guaranteed for programming and
erasure to the VCC pin and 0 V to the VSS pin.
RESET
Reset input
I
Reset input pin.
P4_6/XIN
P4_6 input/clock input
I
Connect a ceramic resonator or crystal oscillator
between pins XIN and XOUT.
P4_7/XOUT
P4_7 input/clock output
I/O
AVCC, AVSS
Analog power supply input I
Connect AVSS to VSS and AVCC to VCC,
respectively.
P1_0 to P1_7
Input port P1
I
Input “H” or “L” level signal or leave the pin open.
P3_3 to P3_5
Input port P3
I
Input “H” or “L” level signal or leave the pin open.
P4_2/VREF
Input port P4
I
Input “H” or “L” level signal or leave the pin open.
MODE
MODE
I/O Input “L”.
P3_7
TXD output
O
Serial data output pin.
P4_5
RXD input
I
Serial data input pin.
