Technical discussions about Freescale (Motorola) DSPs (including the DSP56000, DSP56300, DSP56600, 56800 DSPs).
Our product is medium voltage (4160V) variable frequency drive. It consists of 9~24 power cells depending on the power level of the load. Each power cell has a control board with a DSP56F807 and an Altera EPLD on it. The DSP talks to the EPLD via SPI port and the EPLD talks to a master control board via a fiber optic cable. The drives that we have DSP watch-dogged is used in a coal power plant to control a motor which spins an ID fan. Over the past two months, six power cells' DSPs have been watch-dogged. In our lab, we have been trying to replicate the watch dog event again on the cells that had been watch-dogged at the power plant and sent back to us for diagnosis. We injected conductive and radiated RF (up to over 300MHz and 110dB) to the cells, as well as high power transient. The analog inputs to the DSP A/D were severely disturbed, but so far we have not been able to get the DSP watch-dogged. It is imperative that we find the root cause of the watch dog event and come up with a viable solution for the customer. So I would greatly appreciate it if someone can give some help.
I really need more information to try to help. How are the power cells connected to the
DSP control board? A detailed block diagram would be helpful.
I assume "watch-dogged" means the processor is resetting due to watchdog time outs
due to unknown causes.
linelizabeth <s...@siemens.com> wrote:
Our product is medium voltage (4160V) variable frequency drive. It
consists of 9~24 power cells depending on the power level of the
load. Each power cell has a control board with a DSP56F807 and an
Altera EPLD on it. The DSP talks to the EPLD via SPI port and the
EPLD talks to a master control board via a fiber optic cable.
The drives that we have DSP watch-dogged is used in a coal power
plant to control a motor which spins an ID fan. Over the past two
months, six power cells' DSPs have been watch-dogged.
In our lab, we have been trying to replicate the watch dog event
again on the cells that had been watch-dogged at the power plant and
sent back to us for diagnosis. We injected conductive and radiated RF
(up to over 300MHz and 110dB) to the cells, as well as high power
transient. The analog inputs to the DSP A/D were severely disturbed,
but so far we have not been able to get the DSP watch-dogged.
It is imperative that we find the root cause of the watch dog event
and come up with a viable solution for the customer. So I would
greatly appreciate it if someone can give some help.
The given informations are not sufficient to find the problem. Anyway, in general, I can suggest you to be careful with variables shared from interrupts and the other code. When the normal execution code needs to write to a variable that can be written by an interrupt, too, you have two ways to safely do it: use an atomic write operation, or disable interrupts before writing the variable. If you choose the second one, be sure that the pipeline is exhausted before writing the variable (chapter 7 of DSP56800 Family Manual). The same thing if you have nested interrupts that share variables. If you don't follow these guidelines, you could have watchdog or reset events. Regards, Roberto -----Messaggio originale----- Da: m...@yahoogroups.com [mailto:m...@yahoogroups.com] Per conto di linelizabeth Inviato: mercoledì 16 gennaio 2008 17.19 A: m...@yahoogroups.com Oggetto: [motoroladsp] watch dog on 56f807 Our product is medium voltage (4160V) variable frequency drive. It consists of 9~24 power cells depending on the power level of the load. Each power cell has a control board with a DSP56F807 and an Altera EPLD on it. The DSP talks to the EPLD via SPI port and the EPLD talks to a master control board via a fiber optic cable. The drives that we have DSP watch-dogged is used in a coal power plant to control a motor which spins an ID fan. Over the past two months, six power cells' DSPs have been watch-dogged. In our lab, we have been trying to replicate the watch dog event again on the cells that had been watch-dogged at the power plant and sent back to us for diagnosis. We injected conductive and radiated RF (up to over 300MHz and 110dB) to the cells, as well as high power transient. The analog inputs to the DSP A/D were severely disturbed, but so far we have not been able to get the DSP watch-dogged. It is imperative that we find the root cause of the watch dog event and come up with a viable solution for the customer. So I would greatly appreciate it if someone can give some help.