C-code to control FPGA with Leon

[krebs]

Hallo,
i have a leon Processor and a CAN IP-core. i have connect CAN IP-core
to Leon with APB Slave and the whole Model in bitstream File exported.
The CAN IP-core has defined 32 Register, which also have in leon the
address. Now in the C-Code i want to send a message from CAN IP-core.
Do i only need to write the message in Transffer Register from CAN
IP-core and just let the CommandRegister from CAN IP-core send the
message? and if not, how to send a message and how should i write in
the C-code?

thanks in advance

krebs

 

[Jonathan Bromley]

On 19 May 2004 03:10:58 -0700, kewangke@web.de (krebs) wrote:

i have a leon Processor and a CAN IP-core. i have connect CAN IP-core
to Leon with APB Slave and the whole Model in bitstream File exported.
The CAN IP-core has defined 32 Register, which also have in leon the
address. Now in the C-Code i want to send a message from CAN IP-core.
Do i only need to write the message in Transffer Register from CAN
IP-core and just let the CommandRegister from CAN IP-core send the
message? and if not, how to send a message and how should i write in
the C-code?

It entirely depends on the specific CAN core you are using.
Surely it came with ample documentation to describe how to do
this basic thing? If the core lacks this documentation,
please tell us which core so that we may all avoid it in
the future. If, however, it has such documentation, then
perhaps you can share with us the part that you don't understand.

Traditional CAN modules such as the SJA1000 allow you to create
a message by writing its contents to registers, as you suggest.
You must also remember to configure the identifier and other
features of the message. Then you write some kind of "start"
command to a control register. The message then probably
goes into a FIFO buffer so that it can be sent automatically
by the hardware at some future time. There is probably an
interrupt output, or a status register, allowing you to
determine when the message has been sent. Also, don't
forget to check for the many possible error conditions
that CAN checks so carefully.
--
Jonathan Bromley, Consultant

DOULOS - Developing Design Know-how
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The contents of this message may contain personal views which
are not the views of Doulos Ltd., unless specifically stated.

 

[krebs]

as said, i have to connect the CAN IP-Core with Leon Processor and
implement the whole modul in a FPGA Board.

i have downloaded Leon Core from www.gaisler.com and CAN IP-Core from
www.opencores.com. So there was not much documentation for the CAN
IP-Core. In my Opinion, the CAN IP-Core is quite similar to the
SJA1000 Pelican, but not the same. in my CAN Core, from the Register
10 to 19, it refers to tx_data_0 to tx_data_9, and from Register 20 to
29 refers to rx_data_0 to rx_data_9.

As said, i have connected the CAN Core to Leon as an APB-Slave and to
send a message from Can Core, i have written a C-Code with following
steps:

1) i write the data to tx_data_0 to tx_data_9 register. the tx_data_0
and tx_data_1 Register has the information of the Identifier, RTR and
Data length.

2) then i set the command register of 0x01 to send the message.

3) i have disabled the interrupt register and error register and just
want to sent a message first.

4) to observe the can bus i have the CANalyzer.

Just till now, i have not received single message.