SC73C1402
17. POC circuit
The POC circuit monitors the power supply voltage and applies an internal reset to the micro-controller.
The POC circuit has the following functions:
•Generates an internal reset signal when V
DD
V
POC
note1
.
•Cancels an internal reset signal when V
DD
> V
POC.
Here, V
DD
: power supply voltage, V
POC
: POC detection voltage (including V
POC1
& V
POC2
).
V
DD
3.6V
2.0V
V
POC1
V
POC2
Operating ambient temperature T
amb
=-10°C~+70°C
POC detection @powered on, V
POC1
=1.8V~2.0V
POC detection @voltage droped, V
POC2
=1.2V~1.6V
0V
Internal reset signal
Reset
Note 2
1
Operation mode
Note 3
Notes1. V
POC
is different in different conditions. When powered on, the V
POC
value is V
POC1(
V
POC1
=1.8V~2.0V);
when working, V
POC
is approximately V
POC2
in normal conditions(V
POC2
=1.2V~1.6V).
2. Actually, there is a short oscillation stabilization wait time before the circuit is in operation mode.
The oscillation stabilization wait time is about 2
16
/fmain.
3. The POC circuit generates an internal reset signal when the power supply voltage has fallen.
18. Instruction cycle
Instructions and internal operations are executed in sync with the main clock. The minimum unit of
instruction is called the instruction cycle. SC73C1402 has 1 and 2-cycle OP code instructions.
An instruction cycle consists of 5 states (STCLK1 – STCLK5). Each state consists of 1 main clock.
Therefore, the instruction cycle time is 5/fmain [s].
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http: www.silan.com.cn
REV:1.1
2005.12.19
Page 8 of 20
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