p2125vps20 Renesas Electronics Corporation., p2125vps20 Datasheet - Page 557

• Manufacturer Part Number: p2125vps20
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

19.8
The boot program initiated in boot mode performs transmission and reception with the host PC via
the on-chip SCI. The serial communication interface specifications for the host and boot program
are shown below.
(1)
The boot program has three states.
1. Bit-rate-adjustment state
2. Inquiry/Selection state
3. Programming/erasing state
The boot program states are shown in figure 19.19.
In this state, the boot program adjusts the bit rate to communicate with the host. Initiating boot
mode enables starting of the boot program and transition to the bit-rate-adjustment state. The
boot program receives the command from the host to adjust the bit rate. After adjusting the bit
rate, the boot program enters the inquiry/selection state.
In this state, the boot program responds to inquiry commands from the host. The device name,
clock mode, and bit rate are selected in this state. After selection of these settings, the boot
program makes a transition to the programming/erasing state by the command for a transition
to the programming/erasing state. The boot program transfers the libraries required for erasure
to the on-chip RAM and erases the user MATs and user boot MATs before the transition to the
programming/erasing state.
Programming and erasure by the boot program take place in this state. The boot program is
made to transfer the programming/erasing programs to the on-chip RAM by commands from
the host. Sum check and blank check are executed by sending commands from the host.
Status
Serial Communication Interface Specifications for Boot Mode
Section 19 Flash Memory (0.18-µm F-ZTAT Version)
Rev. 1.00 Sep. 21, 2006 Page 519 of 658
REJ09B0310-0100