TC1796
System Units (Vol. 1 of 2)
Reset and Boot Operation
User’s Manual
4-23
V2.0, 2007-07
Reset, V2.0
Figure 4-3
Flow Diagram of Bootstrap Loader ASC0 Boot Modes
MCA05611
Initialization of ASC0
Bootstrap Loader Mode 1
RXD0A pin = 1?
yes
no
RXD0A pin = 0?
Read System Timer
yes
no
RXD0A pin = 1?
no
yes
Read System Timer
Calculate difference
Unlock WDT
Enable ASC0 clock
Lock WDT
Initialize ASC0 port pins
Calculate baud rate
(search for best values for
FDV and BG registers)
Initialize ASC0 registers
Data byte
received?
no
yes
Store data byte in buffer
Decrement byte counter
Byte
counter = 0?
no
yes
Write word to SPRAM
Increment data pointer
Byte counter = 4
Decrement word counter
Word
counter = 0?
no
yes
Execute jump to
address D4000000
H
Enable receiver
Initialize data pointer
Byte counter = 4
Word counter = 32
Transmit identification D5
H
Ident. byte
transmitted?
no
yes
Baud rate
detection
Baud rate
calculation
and ASC0
setup
Data
receive
loop