EM78P312N
The flag (except ICIF bit) in the Interrupt Status Register (ISFR 2) is set regardless of the status of its mask bit or the execution of ENI. The RETI instruction ends the interrupt routine and enables the global interrupt (the execution of ENI).
5.16 Oscillator
5.16.1 Oscillator Modes
The EM78P312N can operate in two different oscillator modes, i.e., Crystal oscillator mode and External RC oscillator mode (ERC) oscillator mode. User can select which mode by Code Option Register. The maximum limit for operational frequencies of the crystal/resonator under different VDDs is listed below.
Table 10 Oscillator Modes Defined by SDCS and OSC
Mode | OSC | Oscillator |
Single Clock
1 | High frequency oscillator |
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0 | ERC |
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Table 11 The Summary of Maximum Operating Speeds
Condition | VDD | Max. Fxt. (MHz) |
High frequency oscillator
3.0 | 4.0 |
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5.0 | 10.0 |
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5.16.2 Crystal Oscillator/Ceramic Resonators (Crystal)
EM78P312N has a clock generator. i.e. fc (high frequency) which can be driven by an external clock signal through the OSCI pin.
In most applications, Pin OSCI and Pin OSCO can be connected with a crystal or ceramic resonator to generate oscillation. Table 12 provides the recommended values of C1 and C2. Since each resonator has its own attribute, user should refer to its specification for appropriate values of C1 and C2. A serial resistor Rs may be necessary for AT strip cut crystal.
50 • | Product Specification (V1.0) 10.03.2006 |
(This specification is subject to change without further notice)
