upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 611

• Manufacturer Part Number: upd70f3402
• Description: 32-/16-bit Single-chip Microcontroller With Can Interface
• Manufacturer: Renesas Electronics Corporation.

(15) CAN module receive history list register (CnRGPT)
(a) Read
(b) Write
(a) Read
Note: The read value of RGPT0 to 7 is invalid when RHPM = 1.
CnRGPT
CnRGPT
RHPM
RGPT7 to RGPT0
The CnRGPT register is used to read the receive history list.
ROVF
Figure 16-38: CAN Module Receive History List Register (CnRGPT) Format (1/2)
0
1
0
1
0.....31
Note 1
RGPT7 RGPT6 RGPT5 RGPT4 RGPT3 RGPT2 RGPT1 RGPT0
All the message buffer numbers that have not been read are preserved. All the numbers of the
message buffers in which a new data frame or remote frame has been received and stored are
recorded to the receive history list (the receive history list has a vacant element).
At least 23 entries have been stored since the host processor serviced the RHL last time (i.e.
read CnRGPT). The first 22 entries are sequentially stored whereas the last entry might have
been overwritten by newly received messages a number of times because all buffer numbers
are stored at position LIPT-1 when the ROVF bit is set to 1. As a consequence receptions can-
not be completely recovered in the order that they were received.
15
15
7
0
0
7
0
The receive history list has at least one message buffer number that has not been read.
The receive history list has no message buffer numbers that have not been read.
When the CnRGPT register is read, the contents of the element indexed by the
receive history list get pointer (RGPT) of the receive history list are read. These con-
tents indicate the number of the message buffer in which a data frame or a remote
frame has been stored.
14
14
6
0
0
6
0
User’s Manual U16702EE3V2UD00
13
13
5
0
0
5
0
Chapter 16 FCAN Controller
12
12
4
0
0
4
0
Receive history list pointer match
Receive history list overflow bit
Receive history list read pointer
11
11
3
0
0
3
0
10
10
2
0
0
2
0
RHPM
9
1
9
0
1
0
ROVF
ROVF
Clear
8
0
8
0
0
see Table
Address R/W After reset
Address R/W After reset
16-16
R/W
xx02H
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