HD64F7050 RENESAS [Renesas Technology Corp], HD64F7050 Datasheet - Page 359

• Manufacturer Part Number: HD64F7050
• Description: 32-Bit RISC Microcomputer SuperH RISC engine Family/
• Manufacturer: RENESAS [Renesas Technology Corp]

Contention between DCNT Write and Counter Clearing by Underflow: With the channel 10
down-counters (DCNT10A to DCNT10H), if the count is halted due to underflow occurring in the
T2 state of a down-counter write cycle by the CPU, retention of the H'0000 value has priority and
the write to DCNT by the CPU is not performed. Writing of 1 to the interrupt status flag (OSF)
when the underflow occurs is performed in the same way as for normal underflow.
The timing in this case is shown in figure 10.63. In this example, a write of H'5555 to DCNT is
attempted at the same time as DCNT underflows.
Internal write signal
Interrupt status flag
DCNT input clock
Underflow signal
Figure 10.63 Contention between DCNT Write and Underflow
Write data
Address
DCNT
(OSF)
CK
0001
DCNT address
T1
0000
5555
T2
H'0000 retained when DCNT halts
Rev. 5.00 Jan 06, 2006 page 339 of 818
Section 10 Advanced Timer Unit (ATU)
0000
REJ09B0273-0500