SM8951B Datasheet, PDF (16/18 Pages) SyncMOS Technologies,Inc – 8-Bits Micro-controller

SyncMOS Technologies International, Inc.
SM8951B
8-Bits Micro-controller
With4KBFlashROM&128bytesRAM embedded
Watch Dog Timer Register - System Control Register
SCONF ($BFH)
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
WDR
Unused
Unused
Unused
Unused
Unused
Unused
ALEI
WDR : Watch Dog Timer Reset Flag. When system reset by Watch Dog Timer overflow, WDR will be set to 1.
ALEI : ALE output inhibit bit. It can reduce EMI.
The bit 7(WDR) of SCONF is Watch Dog Timer Reset bit. It will be set to 1 when reset signal generated by WDT
overflow. User should check WDR bit whenever un-predicted reset happened.
Reduce EMI Function
The SM8951B allows user to reduce the EMI emission by setting 1 to the bit 0 (ALEI) of SCONF register. This
function will inhibit the clock signal in Fosc/6 Hz output to the ALE pin. This function is available when there is no
external program memory or no external data RAM in the system.
Application Reference
X'tal
3MHz
C1
30 pF
C2
30 pF
R
open
Valid for SM8951B
6MHz
9MHz
30 pF
30 pF
30 pF
30 pF
open
open
12MHz
22 pF
22 pF
open
X'tal
16MHz
25MHz
33MHz
40MHz
C1
22 pF
15 pF
5 pF
2 pF
C2
22 pF
15 pF
5 pF
2 pF
R
open
62KΩ
6.8KΩ
4.7KΩ
Note:
Oscillation circuit may differs with different crystal or ceramic resonator in higher oscillation frequency which was due to each
crystal or ceramic resonator has its own characteristics.
User should check with the crystal or ceramic resonator manufacturer for appropriate value of external components.
X'tal
R
C1
C2
XI
SM8951B
X2
Power Saving Mode
The SM8951B has several features that help the user to control the power consumption of the device. The powers
saving features are basically the Power Down mode, Economy mode and the Idle mode of operation.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M022Ver:BSM8951B
16
06/2009