
19
RAM BACKUP MODE
19-9
32192/32195/32196 Group Hardware Manual
Rev.1.10 REJ09B0123-0110 Apr.06.07
19.4 Exiting RAM Backup Mode (Wakeup)
The processing to place the M32R/ECU out of RAM backup mode and return it to normal operation mode is
referred to as “wakeup” processing. Figure 19.4.1 shows an example of wakeup processing.
Wakeup processing is initiated by applying a reset. The following shows how to execute wakeup processing.
(1) Reset the microcomputer ((a) in Figure 19.4.1).
(2) Set portn for output mode and output a "H" from the port ((b) in Figure 19.4.1) (Note 1)
(3) Compare the RAM content against the RAM check data created before entering RAM backup mode ((c) in
Figure 19.4.1).
(4) If the comparison in (3) did not match, initialize the RAM ((d) in Figure 19.4.1).
If the comparison in (3) matched, use the retained data in the program.
(5) Initialize each internal circuit ((e) in Figure 19.4.1) before returning to the main routine ((f) in Figure 19.4.1).
Note 1: For wakeup from power outage RAM backup mode, portn settings are unnecessary.
Figure 19.4.1 Wakeup Processing
OK
Error
Compare RAM content
against backup RAM
check data
Initialize the RAM
Example of wakeup processing
Reset
Set the transistor's base
connecting pin (portn)
for "H" level output mode
(Note 1)
Initialize each circuit
To the main routine
(a)
(b)
(c)
(d)
(e)
(f)
Note 1: For wakeup from power outage RAM backup mode, portn settings are unnecessary.