
S1C88409 TECHNICAL MANUAL
EPSON
113
CHAPTER 5: PERIPHERAL CIRCUITS AND OPERATION (16-bit Programmable Timer)
5.12.5 Interrupt function
The 16-bit programmable timer can generate an
interrupt with the compare match signal and
underflow signal of each timer.
Figure 5.12.5.1 shows the configuration of the 16-
bit programmable timer interrupt circuit.
The compare match signal and underflow signal of
each timer set the corresponding interrupt factor
flag to "1". At that point, the interrupt is generated.
The interrupt can also be prohibited by setting the
interrupt enable register to correspond with the
interrupt factor flag.
Furthermore, the priority level of the interrupt for
the CPU can be set to an optional level (0–3) using
the interrupt priority register.
Table 5.12.5.1 shows the interrupt factor flags,
interrupt enable registers and interrupt priority
registers corresponding to the interrupt factors.
In the 8-bit mode, the compare match interrupt
factor flag and underflow interrupt factor flag are
individually set to "1" by the timers.
In the 16-bit mode, the interrupt factor flags of
Timer 1 are set to "1" by the compare match and
underflow of 16 bits.
Refer to Section 5.20, "Interrupt and Standby
Mode", for details of the interrupt control registers
and operations subsequent to interrupt generation.
The exception processing vector addresses for the
16-bit programmable timer interrupt are set as
follows:
Timer 0 underflow interrupt:
000010H
Timer 0 compare match interrupt: 000012H
Timer 1 underflow interrupt:
000014H
Timer 1 compare match interrupt: 000016H
16-bit programmable timer 1
Data
bus
Timer 0
interrupt request
Address
Underflow
Interrupt factor flag
FTU0
Address
Interrupt enable
register ETU0
Timer 1
interrupt request
Address
Compare match
Interrupt factor flag
FTC0
Address
Interrupt enable
register ETC0
Interrupt priority
level judgment
circuit
Address
Interrupt priority register
PTM00, PTM01
16-bit programmable timer 0
Fig. 5.12.5.1 Configuration of 16-bit programmable timer interrupt circuit
Table 5.12.5.1 Interrupt control registers
16-bit
programmable
timer 0
16-bit
programmable
timer 1
Interrupt factor
Interrupt factor flag
Counter underflow
Compare match between counter and
compare data register CDR0
Counter underflow
Compare match between counter and
compare data register CDR1
Name
FTU0
FTC0
FTU1
FTC1
AddressDx
00FF28HD3
00FF28HD4
00FF28HD5
00FF28HD6
Interrupt enable register
Name
ETU0
ETC0
ETU1
ETC1
AddressDx
00FF24HD3
00FF24HD4
00FF24HD5
00FF24HD6
Interrupt priority register
Name
PTM00
PTM01
PTM10
PTM11
AddressDx
00FF20HD0
00FF20HD1
00FF20HD2
00FF20HD3