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(1) Reception of trace message
1.
Specify whether the trace message is 16 or 64 bytes by using the J0SZ bit of the MDSOHR register
(Section trace message). In the default mode, both the J0 message size is 64 bytes.
2.
Set a 2-byte synchronization pattern that indicates the beginning or end of the message to the J0PTN[15:0]
bits and J0M[15:0] bits of the J0PTN registers(Section trace message). Set a pattern to be detected to the
J0PTN[15:0] bits, and specify the bits of the bit string of the J0M[15:0] bits that are treated as Don't Care
bits, to the J0PTN[15:0] bits.
3.
Specify whether the set synchronization pattern is the beginning or end of the message to the J0SYNC bit
of the MDSOHR register. By default, the pattern is assumed to be an end pattern.
For example, to have one byte with the MSB set to 1 (1xxxb) be recognized as the end pattern of the message,
the setting is as follows, and the J0SYNC bit of MDSOHR register is set to 0.
J0PTN
J0M
Pattern to be detect
The µ PD98413 stores the data at the J0 byte position of the receive frame, in order, into Captured buffer,
4.
checking the contents of the data string each time it is updated. When the data string stored in Captured
buffer satisfies the three conditions listed below, the data is stored in the Expected Buffer, and the JLOCK
bit of the CMTMR register is set to 0 and, at the same time, the J0M bit of the DPPER register is set to post
notification of the arrival of a new message to the CPU. The setting of the J0M bit can be used to trigger an
interrupt. If the J0LOCK bit of the CMTMR register status is 1, the trace message that is stored to Expected
buffer is kept and not overwrite, and then if µ PD98413 detect new message, that is aborted internally.
Detecting Trace message condition is as follows.
Condition 1. The synchronization pattern is contained in receive message.
Condition 2. The same message is received three or more time in a row.
Condition 3. The received message is different from message that is contained Captured buffer.
5.
When the CPU has been informed of reception of a new message, to receive the next message, it sets to 0
the J0LOCK bit of the CMTMR register (if the data of Expected buffer has already been read by the CPU
and can be overwritten by the new message).
6.
The data of the message stored in the Accepted buffer has been automatically rearranged by the
µ PD98413. If a synchronization pattern is specified at the beginning of a message, the data has been
rearranged so that the synchronization pattern is at the beginning of the buffer (pointer = 00H). If the
synchronization pattern is specified as the end byte of the message, the data is rearranged so that the
synchronization pattern is at the end of the message.
104
CHAPTER 3 FUNCTIONAL OUTLINE
1000 0000 0000 0000
0111 1111 1111 1111
1xxx xxxx xxxx xxxx
PRELIMINARY
Detected Pattern Position
J0SYNC bit
Specifies end of the message
0
Specifies head of the message
1
NEC confidential and Proprietary
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