NEC V850E/RS1 User Manual page 611

(15) CAN module receive history list register (CnRGPT)
The CnRGPT register is used to read the receive history list.
(a) Read
CnRGPT
(b) Write
CnRGPT
(a) Read
RGPT7 to RGPT0
RHPM
Note: The read value of RGPT0 to 7 is invalid when RHPM = 1.
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Figure 16-38: CAN Module Receive History List Register (CnRGPT) Format (1/2)
15 14 13
RGPT7 RGPT6 RGPT5 RGPT4 RGPT3 RGPT2 RGPT1 RGPT0
7 6 5
0 0 0
15 14 13
0 0 0
7 6 5
0 0 0
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-
0.....31
tents indicate the number of the message buffer in which a data frame or a remote
frame has been stored.
Note 1
0 The receive history list has at least one message buffer number that has not been read.
1 The receive history list has no message buffer numbers that have not been read.
ROVF
All the message buffer numbers that have not been read are preserved. All the numbers of the
0 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
1 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.
User's Manual U16702EE3V2UD00
Chapter 16 FCAN Controller
12 11 10
4 3 2
0 0 0
12 11 10
0 0 0
4 3 2
0 0 0
Receive history list read pointer
Receive history list pointer match
Receive history list overflow bit
9 8 Address R/W After reset
R/W
see Table
1 0
16-16
RHPM ROVF
9 8 Address R/W After reset
0 0
1 0
Clear
0
ROVF
xx02H
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