Interrupt Trigger Modes - Epson S1C17001 Technical Manual

6 INITERRUPT CONTROLLER

6.3.5 Interrupt Trigger Modes

The ITC includes two trigger modes – pulse trigger mode and level trigger mode – which enable acceptance of in-
terrupt requests setting the EIFT flag as pulse or level signals.
Trigger mode can be selected using the EITGx bits within the ITC_ELVx register (0x4306 to 0x4308). Setting the
EITGx bits to 1 selects the level trigger mode; setting them to 0 (default) selects pulse trigger mode.
Note: All EITGx bits should be set to 1 (level trigger mode) for the S1C17001.
Hardware interrupt
P0 port interrupt
P1 port interrupt
Stopwatch timer interrupt
Clock timer interrupt
8-bit OSC1 timer interrupt
PWM & capture timer interrupt
The module setting the IIFT flag outputs a pulse signal only as the interrupt request to the ITC. No trigger mode
selector bit is provided.
Pulse trigger mode
In pulse trigger mode, the ITC samples the interrupt signal using the system clock rising edge. If a pulse High
period is detected, the ITC sets the interrupt flag (IIFTx) to 1 and stops sampling that interrupt signal. The ITC
resumes sampling of the interrupt signal after the application program resets the interrupt flag (IIFTx) to 0 (via
interrupt processing routine).
pclk
Interrupt signal from
interrupt source
Interrupt flag
within ITC
Note: The S1C17001 interrupts listed below are in pulse trigger mode. If an interrupt occurs, reset
the interrupt flag IIFTx (to 1) within the interrupt processing routine.
• 8-bit timer interrupt
• 16-bit timer Ch.0 interrupt
• 16-bit timer Ch.1 interrupt
• 16-bit timer Ch.2 interrupt
• UART interrupt
• Remote controller interrupt
• SPI interrupt
2
• I C interrupt
34
Table 6.3.5.1: Trigger mode selector bits
Trigger mode selector bit
EITG0 (D4/ITC_ELV0 register)
EITG1 (D12/ITC_ELV0 register)
EITG2 (D4/ITC_ELV1 register)
EITG3 (D12/ITC_ELV1 register)
EITG4 (D4/ITC_ELV2 register)
EITG7 (D12/ITC_ELV3 register)
Reset when software writes 1 to interrupt flag
Figure 6.3.5.1: Pulse trigger mode
EPSON
Register address
0x4306
0x4306
0x4308
0x4308
0x430a
0x430c
S1C17001 TECHNICAL MANUAL