Unread Message Status Register (Umsr) - Renesas H8SX/1500 Series Hardware Manual

Section 13 Controller Area Network (HCAN)

13.3.16 Unread Message Status Register (UMSR)

UMSR indicates that a received message which has not been read is overwritten by a new receive
message. In this case, the message which has not been read is lost.
Bit 15
Bit Name UMSR7
Initial Value 0
R/W R/(W)*
Bit 7
Bit Name UMSR15
Initial Value 0
R/W R/(W)*
Note: * Only 1 can be written to these bits, to clear the flags.
Bit Bit Name
15 UMSR7
14 UMSR6
13 UMSR5
12 UMSR4
11 UMSR3
10 UMSR2
9 UMSR1
8 UMSR0
7 UMSR15
6 UMSR14
5 UMSR13
4 UMSR12
3 UMSR11
2 UMSR10
1 UMSR9
0 UMSR8
Note: * Only 1 can be written to clear the flag.
Rev. 3.00 Mar. 14, 2006 Page 474 of 804
REJ09B0104-0300
14 13
UMSR6 UMSR5 UMSR4
0 0
R/(W)* R/(W)*
6 5
UMSR14 UMSR13 UMSR12
0 0
R/(W)* R/(W)*
Initial
Value R/W
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
0 R/(W)*
12 11
UMSR3 UMSR2
0 0
R/(W)* R/(W)* R/(W)*
4 3
UMSR11 UMSR10
0 0
R/(W)* R/(W)* R/(W)*
Description
The received message has been overwritten by a
new message before being read.
[Setting condition]
•
When a new message is received before
RXPR is cleared
[Clearing conditions]
•
Writing 1
10 9 8
UMSR1 UMSR0
0 0 0
R/(W)* R/(W)*
2 1 0
UMSR9 UMSR8
0 0 0
R/(W)* R/(W)*