Emanuele Ziglioli

Processor Expert: can't enable Chip Selects in SynchroMaster bean

Discussion created by Emanuele Ziglioli on Oct 29, 2008
Latest reply on Nov 3, 2008 by Emanuele Ziglioli

CodeWarrior: 7.1
CPU: MCF54452

I have a number of peripherals on the SPI port and I'm trying to control them via SynchroMaster beans.

Though I get an error when I try to enable any Slave select pin with Output direction.
The error is "This setting is not supported".

But I'm pretty sure there's hardware support within our CPU for hardware chip select.
In fact there are 5 chip select lines.

As a result of this error, the PAR_DSPI register doesn't set any of the DSPI lines to chip select.

I've got also another question.
The SM1_SendChar() function takes an 8 bit unsigned values and writes it to register DSPI_PUSHR.
That register though is a 32 bit one and the upper 16 bits contain information such as the chip select line.
In the generated code, the upper 24 bits appear to be always 0, since a straight copy is done from the 8-bit input value to the 32-bit register.
Therefore, I wouldn't expect to see any chip select line being controlled when a byte is written to SPI.
How could that work?


Message Edited by ZiglioNZ on 2008-10-29 03:15 AM

Message Edited by ZiglioNZ on 2008-10-29 03:39 AM