R01UH0823EJ0100 Rev.1.00
Page 1711 of 1823
Jul 31, 2019
RX23W Group
50. Flash Memory (FLASH)
50.10 Communication Protocol
This section describes the protocol used in boot mode. When developing a serial programmer, control with this
communication protocol.
50.10.1
State Transition in Boot Mode (SCI Interface)
shows the Boot Mode (SCI Interface) State Transition.
Figure 50.31
Boot Mode (SCI Interface) State Transition
(1) Bit rate automatic adjustment state
In this state, the bit rate is automatically adjusted to 9,600 or 19,200 bps for communication with the host.
When the bit rate adjustment is completed, the MCU sends 00h to the host. After that, when the MCU receives 55h
sent from the host, the MCU sends E6h to the host, and enters the inquiry/setting host command wait state.
The host must not send data until 400 ms elapse after a reset of the MCU is released.
(2) Inquiry/setting host command wait state
In this state, the host can make inquiries for the MCU information including block configuration, size, and
addresses where the user area and data area are allocated, and select the endian of data and a bit rate.
When the MCU receives the program/erase host state transition command from the host, it determines whether boot
mode ID code protection is enabled or disabled. If boot mode ID code protection is disabled, the MCU enters the
inquiry/setting host command wait state. If boot mode ID code protection is enabled, the MCU enters the boot mode
ID code authentication state.
Refer to
section 50.10.5, Inquiry Commands
section 50.10.6, Setting Commands
for details on
inquiry/setting commands.
55h
Inquiry/setting command
Response
(2)
Read-check command
Response
Block erase
Program
ID code
protection disabled
Program preparation
Program
completed
(1)
(4)
Inquiry/setting host
command wait state
Boot mode ID code
authentication state
Inquiry/setting host
command execution state
Bit rate automatic
adjustment state
Program/erase host
command wait state
Read-check host command
execution state
Program wait state
Erase wait state
Erase
com
pleted
Erase
prepa
ration
(3)
Program/erase
Start up in boot mode
(for SCI interface)
ID code
protection enabled