RE: GPIO software design question

With TINI 1.12, the ALE is default disabled upon bootup. I have to write a
native method that implements the following:

                mov     pmr, #10000010b                    ; Set for crystal
* 2
                mov     pmr, #10010010b                    ; Enable
multiplier
WaitCrystal:
                mov     a, exif                            ; Wait for
multiplier to be ready
                jnb     acc.3, WaitCrystal                 ; Jump if CKRY is
low
                mov     pmr, #00010010b                    ; Go to crystal *
2

This enables the ALE to output a clock signal when a process is running, as
Bryan has described.

This same code is in the Keil C startup code =)

Simon Wong

-----Original Message-----
From: Bryan Armstrong [mailto:bryan.armstrong-6tN4nzCoH/[email protected]]
Sent: Thursday, January 08, 2004 6:54 AM
To: Venelin Efremov
Cc: swong-5bdsyQ5pCqFWk0Htik3J/[email protected]; [email protected]
Subject: Re: [TINI]GPIO software design question


Venelin Efremov wrote:
> On board CPLD won't help you much, since it has no clock input., so you
can
> not load 8 bits and expect it to send them automatically.
> Writing in ASM is the key, I managed to get around 1MBps using double
clock
> speed.
>
> ~Venelin

It is possible to use ALE which comes in on IO22 from the TINIs400
schematic for the CPLD clock.  The ALE signal is 1/4, 1/2, or 1/1 of the
CPU crystal frequency depending on if you single, double, or quadruple
it internally on the DS80C400.


--
--
Bryan Armstrong
bryan.armstrong-6tN4nzCoH/[email protected]

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