em78p613 ELAN Microelectronics Corp, em78p613 Datasheet - Page 30

• Manufacturer Part Number: em78p613
• Description: Universal Serial Bus Series Microcontroller
• Manufacturer: ELAN Microelectronics Corp

EM78P613
Universal Serial Bus Series Microcontroller
26 •
7.6.2 Dual Clock Mode
The EM78P613 has one internal oscillator for power saving application. Clearing the
Bit IOCE [7] will enable the low frequency oscillator. At the same time, the external
oscillator will be turned off. Then the MCU will run under very low frequency to
conserve power. Four types of frequency are available for selection in setting bits
IOCA [6, 7].
The USB Host Resume Interrupt can only be used in this mode. If this interrupt is
enabled, the MCU will be interrupted when the USB Host Resume signal is detected on
USB Bus.
7.7 Interrupt
The EM78P613 has one interrupt vector in 0x0001. When an interrupt occurs during
an MCU program run, it will jump to the interrupt vector (0x0001) and execute the
instructions sequentially from the interrupt vector. RF is the interrupt status register,
which records the interrupt status in the relative flags/bits.
The interrupt condition could be one of the following:
TCC Overflow: When the Timer Clock / Counter Register (R1) overflows, the status
Port 7 State Change: When the input signals in Port 7 changes, the status flag RF[4]
EP0 Interrupt: When the UDC successfully accepts a setup transaction from host to
USB Suspend: When UDC detects a USB Suspend signal on the USB bus, the status
USB Reset: When the UDC detects a USB Reset signal on the USB bus, the status
USB Host Resume: When the UDC detects that the USB bus is no longer in Suspend
IOCF is an interrupt mask register which can be set bit by bit. While their respective bit
is written to 0, the hardware interrupt will be inhibited, that is, the EM78P613 will not
jump to the interrupt vector to execute instructions. But the interrupt status flags still
records the conditions no matter whether the interrupt is masked or not. The interrupt
status flags must be cleared by firmware before leaving the interrupt service routine
and enabling other interrupt.
The global interrupt is enabled by the ENI (RETI) instruction and is disabled by the DISI
instruction.
flag RF[0] will be set to 1. Its Interrupt Vector is 0X0001.
will be set to 1. Its Interrupt Vector is 0X0001.
EndPoint0, the status flag RF[1] is set to 1. Its Interrupt Vector is
0X0001.
flag RF[2] is set to 1. Its Interrupt Vector is 0X0001.
flag R[3] is set to 1. Its Interrupt Vector is 0X0001.
condition and without Device Resume signal, the status flag R[7] is set
to 1. Its Interrupt Vector is 0X0001.
(This specification is subject to change without further notice)
Product Specification (V1.0) 01.09.2009