![Aeroflex Gaisler RT-SPW-ROUTER Скачать руководство пользователя страница 33](http://html1.mh-extra.com/html/aeroflex-gaisler/rt-spw-router/rt-spw-router_user-manual_2862505033.webp)
AEROFLEX GAISLER
33
RT-SPW-ROUTER
Copyright Aeroflex Gaisler AB
June 2012, Version 1.2
There is a user accessible destination key register which is compared to destination key field in incom-
ing packets. If there is a mismatch and a reply has been requested the error code in the reply is set to
3. Replies are sent if and only if the ack field is set to ‘1’.
When a failure occurs during a bus access the error code is set to 1 (General Error). There is predeter-
mined order in which error-codes are set in the case of multiple errors in the core. It is shown in table
31.
Read accesses are performed on the fly, that is they are not stored in a temporary buffer before trans-
mitting. This means that the error code 1 will never be seen in a read reply since the header has
already been sent when the data is read. If the AHB error occurs the packet will be truncated and
ended with an EEP.
Errors up to and including Invalid Data CRC (number 8) are checked before verified commands. The
other errors do not prevent verified operations from being performed.
The details of the support for the different commands are now presented. All defined commands
which are received but have an option set which is not supported in this specific implementation will
not be executed and a possible reply is sent with error code 10.
3.5.5.3
Write commands
The write commands are divided into two subcategories when examining their capabilities: verified
writes and non-verified writes. Verified writes have a length restriction of 4 bytes and the address must
be aligned to the size. That is 1 byte writes can be done to any address, 2 bytes must be halfword
aligned, 3 bytes are not allowed and 4 bytes writes must be word aligned. Since there will always be
only on AHB operation performed for each RMAP verified write command the incrementing address
bit can be set to any value.
Non-verified writes have no restrictions when the incrementing bit is set to 1. If it is set to 0 the num-
ber of bytes must be a multiple of 4 and the address word aligned. There is no guarantee how many
words will be written when early EOP/EEP is detected for non-verified writes.
Table 18. The order of error detection in case of multiple errors in the GRSPW. The error detected first has number 1.
Detection Order
Error Code
Error
1
12
Invalid destination logical address
2
2
Unused RMAP packet type or command code
3
3
Invalid destination key
4
9
Verify buffer overrun
5
11
RMW data length error
6
10
Authorization failure
7*
1
General Error (AHB errors during non-verified writes)
8
5/7
Early EOP / EEP (if early)
9
4
Invalid Data CRC
10
1
General Error (AHB errors during verified writes or RMW)
11
7
EEP
12
6
Too Much Data
*The AHB error is not guaranteed to be detected before Early EOP/EEP or Invalid Data CRC. For very long accesses
the AHB error detection might be delayed causing the other two errors to appear first.