NXP Semiconductors MPC5566 - Watchpoint Messaging

Nexus
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 25-91
25.17.6.1 Watchpoint Messaging
Enabling watchpoint messaging is accomplished by setting the watchpoint messaging enable bit,
DC1[WEN]. Using the BWC1 and BWC2 registers, two independently controlled internal watchpoints
can be initialized. When a DMA access address matches on BWA1 or BWA2, a watchpoint message is
transmitted.
The Nexus module provides watchpoint messaging using the TCODE. When either of the two possible
watchpoint sources asserts, a message is sent to the queue to be messaged out. This message indicates the
watchpoint number.
Figure 25-69. Watchpoint Message Format
25.17.6.2 Watchpoint Error Message
An error message occurs when a new message cannot be queued due to the message queue being full. The
FIFO discards messages until it has completely emptied the queue. After it is emptied, an error message is
queued. The error encoding indicates which types of messages attempted to be queued while the FIFO was
being emptied.
If only a watchpoint message attempts to enter the queue while it is being emptied, the error message
incorporates the watchpoint only error encoding (00110). If a data trace message also attempts to enter the
queue while it is being emptied, the error message incorporates error encoding (01000).
Error information is messaged out in the following format (refer to Figure 25-70).
Figure 25-70. Error Message Format
Table 25-61. Watchpoint Source Description
Watchpoint Source (4 bits) Watchpoint Description
XXX1 Reserved
XX1X Reserved
X1XX Internal Watchpoint #1 (BWA1 match)
1XXX Internal Watchpoint #2 (BWA2 match)
WPHIT (XXXX)
MSB LSB
12
SRC TCODE (001111)
3
6 bits4 bits4 bits
Fixed length = 14 bits
ECODE (00110 / 01000)
MSB LSB
12
SRC TCODE (001000)
3
6 bits4 bits5 bits
Fixed length = 15 bits