R01UH0823EJ0100 Rev.1.00
Page 1731 of 1823
Jul 31, 2019
RX23W Group
50. Flash Memory (FLASH)
50.11.1
Bit Rate Automatic Adjustment Procedure
The MCU measures the low width of data 00h that is sent from the serial programmer at 9,600 or 19,200 bps to
automatically adjust the bit rate.
Figure 50.32
Transmit/Receive Data for Bit Rate Automatic Adjustment
After starting up in boot mode, wait for at least 400 ms and then send 00h to the MCU from the serial programmer. When
the bit rate adjustment is completed, the MCU sends 00h to the programmer. When the programmer receives 00h, send
55h to the MCU from the programmer. When the programmer can not receive 00h, wait for at least 1 ms and send 00h to
the MCU again. When the programmer fails to receive 00h even if it send 00h 30 times, restart the MCU in boot mode
and perform the automatic adjustment for the bit rate again.
When the MCU receives 55h, the MCU sends E6h and enters the inquiry/setting command wait state. If the MCU fails to
receive 55h, the MCU sends FFh. When the programmer receives FFh, restart the MCU in boot mode, and perform the
automatic adjustment for the bit rate again.
Figure 50.33
Bit Rate Automatic Adjustment Procedure
At least 1 ms
between commands
Reception from
the MCU
Transmission to
the MCU
(1)
(2)
(3)
*1
...
Note 1. Maximum 30 times
00h
00h
00h
00h
55h
00h
Note 1. When a value other than 00h is received, restart in boot mode and send a bit rate automatic adjust
command again.
Note 2. When FFh is returned, restart in boot mode and send a bit rate automatic adjust command again.
Serial
programmer
Measure 9-bit
length
00h (maximum 30 times)
00h (automatic adjustment completed)
55h (automatic adjustment confirmed)
E6h (55h received successfully) or FFh (error)
Wait for 400 ms
See
Note 1
See
Note 2
MCU
Release the
reset