Baud Rate of RF100 - SPI

[aravind]

I'm trying to interface a micro-controller with the RF100 via SPI. What is the maximum Baud Rate that can be supported by the RF100 module?

[gvoce]

This information can be found in the SNAP reference manual under performance metrics ......

SPI Byte Transfer Time

The actual SPI transfers are done using “bit banging” in software. This was measured using a logic analyzer at 140 μs per byte.

[gvoce]

Good information can be found about the SPI interface by doing a search on the forum .........

http://forums.synapse-wireless.com/s...&highlight=spi

[Jheath]

Note that for SPI (and I2C) the RF Engine must be the master device (i.e. the one driving the clock).

[aravind]

Thanks!

140us per byte equates to about 57143 bits per second or 57143 Baud.
I guess the UART is faster than the SPI with a Baud Rate of 115200. (UART is the fastest in RF100).

For my application I think I'll have to switch over to UART from SPI as I really require a high Baud Rate.

Please correct me if I am worng.

[Jheath]

UART is the most flexible and usually the fastest interface.

I would suggest using the hardware flow-control (RTS/CTS pins and software) if you are going to run at high speeds.

[aravind]

I was trying out UART today with the flow control enabled. I have a few questions in mind:

1. Is it possible to see the contents of received data from a UART port. For example: Is a statement like "print DS_UART0" valid? This can be helpful to see if a data has been received in the Event Log in Portal for debugging purposes.

2. I believe that CTS is triggered by the RTS signal for the RF100. Is the time lag between an RTS input signal and the CTS output signal 1 ms?

3. Is there a full-duplex transfer of data between the UART port and the externally interfaced peripheral or is it half-duplex?

Thanks in advance!

[Jheath]

@aravind

I think your questions would be answered with a little playing and a quick glance over the "switchboard" section of the SNAP Reference manual.

SNAP allows for UART interaction by either crossConnecting or uniConnecting the UART (as a source or sink) to various other elements of the switch board.

For example, if you wanted to simple forward on all packets you receive on the UART1 to a remote destination you would do the following (we call this datamode or transparent mode):

    crossConnect(DS_UART1, DS_TRANSPARENT)
    ucastSerial(otherNodeAddr)

If you wanted to process UART1 data in your script, then something like this.

uniConnect(DS_STDIO, DS_UART1 )
...
@setHook(HOOK_STDIN)
def incoming(...):
     <<yada yada>>

Of course, you can mix and match connections.

More Info here: http://forums.synapse-wireless.com/s...t=crossConnect

and through using the search tool at the tool of the forum page