Robert Coie <[EMAIL PROTECTED]> writes:
> I am working on an FIR driver for the Vr4121 (which, of course, if
> ever becomes functional, will be contributed), and have some areas of
> confusion:
Do you know the name of the IrDA controller unit and transceiver. For FIR
you usually need to know the details of both. I guess the Vr4121 is some
sort of super-IO that includes the IrDA controller chip, right?
> The FIR and SIU are separate devices, and can both be used at the same
> time provided they are not both trying to use the IrDA tranceiever.
> In other words, if the SIU is using the RS232 pins, then the IrDA
> tranceiver is free for use by the FIR unit.
>
> If this is true, we would theoretically be able to (for example) use
> IrLAN to make a network connection while keeping the console on the
> serial port.
Should be no problem if you could route the output of the serial port to a
different pin on the super-IO. This is possible with all the chipsets I
have looked at, since a laptop manufacturer can choose if the UART is to be
used for a serial port, or for IrDA. You usually select this in one of the
registers of the super-IO.
> Does anyone know if this is in fact true, or are the FIR and SIU
> mutually exclusive at some more basic level, which would render my
> dream impossible?
One problem however is that both the UART and the FIR chip may use the same
interrupt line :-( A clever driver could however check both chips in the
interrupt handler (which shouldn't take much more time).
> The other thing about which I am extremely confused is the meaning of
> the transmit and receive FIFOs referred to by the TDR, RDR and FSR
> registers. The docs talk about the "address to which data is written
> to the tranmit store FIFO" and such, but only 8 bits of the register
> are used. Is there a base register somewhere that must be set, off
> which TDR/RDR is an index? Is the FIFO memory something that I (the
> driver) must provide the FIR unit, or is it provided by the driver?
> How does one access it with only an 8 bit address? Is it in some
> magical place which can only be acccessed with DMA?
FIFO's are impl. as a ... FIFO ;-) You just write/read several times to the
same address.
> Any advice would be greatly appreciated, and if anyone else is working
> on something similar I would love to hear from you. Thank you for
> your time.
I have impl. working FIR drivers for the NSC PC87108, Winbond W83977, IBM
31T1502, and are still struggling with the Sharp UIRCC and VLSI VL82C14 ;-)
Please mail me and the Linux-IrDA mailing list with any question you may
have about IrDA and FIR driver.
-- Dag
--
/ Dag Brattli | The Linux-IrDA Project /
// University of Tromsoe, Norway | Infrared communication for Linux //
/// http://www.cs.uit.no/~dagb | http://www.cs.uit.no/linux-irda/ ///
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