h8s-2635 Renesas Electronics Corporation., h8s-2635 Datasheet - Page 691

• Manufacturer Part Number: h8s-2635
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

16.2.16 Unread Message Status Register (UMSR)
The unread message status register (UMSR) is a 16-bit readable/writable register containing status
flags that indicate, for individual mailboxes (buffers), that a received message has been
overwritten by a new receive message before being read. When a message is overwritten by a new
receive message, the old data is lost.
Bits 15 to 0—Unread Message Status Flags (UMSRx): Status flags indicating that an unread
receive message has been overwritten.
Bit x: UMSRx
0
1
Initial value:
Initial value:
Note: * Only 1 can be written, to clear the flag to 0.
UMSR
R/W:
R/W:
Bit:
Bit:
UMSR15 UMSR14 UMSR13 UMSR12 UMSR11 UMSR10
UMSR7
R/(W) *
R/(W) *
Description
[Clearing condition]
Unread receive message is overwritten by a new message
[Setting condition]
15
0
7
0
Writing 1
When a new message is received before RXPR is cleared
UMSR6
R/(W) *
R/(W) *
14
0
6
0
UMSR5
R/(W) *
R/(W) *
13
0
5
0
UMSR4
R/(W) *
R/(W) *
12
Section 16 Controller Area Network (HCAN)
0
4
0
Rev. 6.00 Feb 22, 2005 page 631 of 1484
UMSR3
R/(W) *
R/(W) *
11
0
3
0
UMSR2
R/(W) *
R/(W) *
10
0
2
0
REJ09B0103-0600
UMSR1
R/(W) *
UMSR9
R/(W) *
9
0
1
0
(Initial value)
UMSR0
R/(W) *
UMSR8
R/(W) *
8
0
0
0