Re: The ROR bug - seems it wasn't a bug after all.

From: A. Fachat <*afachat_at_gmx.de*> Date: Mon, 12 Feb 2024 16:38:02 +0100 Message-ID: <76d53222-82e8-44e1-a1dd-a46a5080d0ee_at_gmx.de> · afachat_at_gmx.de

Am 12.02.24 um 16:34 schrieb Gerrit Heitsch:
> On 2/12/24 15:27, A. Fachat wrote:
>>
>> Am 12.02.24 um 11:25 schrieb didier derny:
>>> Frankly I don't know why it's a bug or not
>>> The essential is that finally they made a great processor that powered
>>> our machines...
>>>
>>> I am more concerned by the w65c51 and the w65c816 still sold knowing
>>> that the w65c51 is unusable and the w65c816 crippled by bugs In
>>> emulation mode
>>>
>> I know the 6551 has ... problems ...
>
> With the 6551 it depends on the version... The NMOS 6551 has a problem
> with /CTS turning off the transmitter immediately, even if that's in
> the middle of a byte being sent. It's documented in the data sheet.
>
> On the w65C51 the transmitter empty bit doesn't work.
>
> I think the old 65C51 did work properly, but was a bit limited with
> the baud rates.
>
> I'd try to hook up a 16550 to a 6502 if I needed a UART for a new design.

The 16550 is my default actually for many years now.

André