HD6475328-CP10 HITACHI [Hitachi Semiconductor], HD6475328-CP10 Datasheet - Page 234

• Manufacturer Part Number: HD6475328-CP10
• Description: original Hitachi CMOS microcomputer unit (MCU)
• Manufacturer: HITACHI [Hitachi Semiconductor]

11.3.4 Setting of TCNT Overflow Flag
The overflow flag (OVF) is set to “1” when the timer count overflows (changes from H'FF to
H'00). Figure 11-7 shows the timing of this operation.
11.4 CPU Interrupts and DTC Interrupts
The 8-bit timer can generate three types of interrupts: compare-match A and B (CMIA and
CMIB), and overflow (OVI). Each interrupt is requested when the corresponding enable and flag
bits are set in the TCR and TCSR. Independent signals are sent to the interrupt controller for each
type of interrupt. Table 11-3 lists information about these interrupts.
Table 11-3 8-Bit Timer Interrupts
Interrupt
CMIA
CMIB
OVI
The CMIA and CMIB interrupts can be served by the data transfer controller (DTC) to have a data
transfer performed.
When the DTC serves one of these interrupts, it automatically clears the CMFA or CMFB flag to
“0.” See section 6, “Data Transfer Controller” for further information on the DTC.
ø
TCNT
Internal overflow
signal
OVF
Description
Requested when CMFA is set
Requested when CMFB is set
Requested when OVF is set
Ø
Figure 11-7 Setting of Overflow Flag (OVF)
H’FF
218
DTC Service Available?
Yes
Yes
No
H’00
Priority
High
Low