Document Number: 002-04578 Rev. *A
Page 17 of 64
MB90910 Series
11. Stabilization of power supply voltage
A sudden change in the power supply voltage may cause the device to malfunction even within the specified V
CC
power supply voltage
operating guarantee range. Therefore, the V
CC
power supply voltage should be
stabilized.
For reference, the power supply voltage should be controlled so that V
CC
ripple variations (peak-to-peak value) at commercial
frequencies (50 Hz/60 Hz) fall below 10
of the standard V
CC
power supply voltage and the coefficient of transient fluctuation does
not exceed 0.1 V/ms at instantaneous power switching.
12. Initialization
In the device, there are internal registers which are initialized only by a power-on reset. To initialize these registers, turn on the power
again.
13. Notes on using CAN function
To use CAN function, please set ’1’ to DIRECT bit of CAN direct mode register (CDMR) .
If DIRECT bit is set to ’0’ (initial value) , wait states will be performed when accessing CAN registers.
Note : Please refer to Hardware Manual of “MB90910 series for detail of CAN Direct Mode Register”.
14. Flash security function
The security bit is located in the area of the Flash memory.
If protection code 01
H
is written in the security bit, the Flash memory is in the protected state by security.
Therefore, please do not write 01
H
in this address if you do not use the security function.
Please refer to following table for the address of the security bit.
15. Correspondence with T
A
105 °C or more
If used exceeding T
A
105 °C, please consult with us due to the restricted reliability.
It is ensured to write/erase data to the Flash memory between T
A
40 °C and
105 °C.
Flash memory size
Address for security bit
MB90F912BS
Embedded 1 Mbit Flash Memory
FE0001
H
