On Wed, 23 May 2007 09:06:12 -0700
David Brownell wrote:
>
> Chipselect zero ... I've had one report that this driver has some issues
> on that chipselect. There seem to be two errata in conflict here:
>
> - One saying that when the controller manages chipselects, it
> does so incorrectly ... releasing it before it's told to do so,
> which prematurely terminates transactions. ("NPCSx rises if
> no data is to be transmitted")
>
> - Another saying that if it does *not* manage chipselects, then
> broken mode fault detect logic kicks in; this could be what
> you're seeing. ("Mode Fault does not allow more than one
> master on Chip Select 0")
>
David, as I understood new atmel_spi driver enables CONFIG_SPI_AT91_MANUAL_CS
which in turn enables workaround for 1st errata item you mentioned
at91rm9200_devices.c
...
in at91_add_device_spi function:
#ifdef CONFIG_SPI_AT91_MANUAL_CS
at91_set_gpio_output(cs_pin, 1);
#else
at91_set_A_periph(cs_pin, 0);
#endif
Regarding second errata item - I have a single device (dataflash - 8MB) on SPI
chip select 0,
so I do not think this is an issue here.
Best regards, Ivan
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