🚀 go-pugleaf

James Williams, <elejw@ccu1.aukuni.ac.nz>, writes:
>I am working on aproject using the V25 cpu, made by NEC. The v25 is 80186
>compatible, with serial ports, dma, etc, all on chip. ...

Well, not quite 'compatible', though very similar the built-in peripherals
are a little different and vary in their functionality.

> ...  Anyway, I am having trouble using the Special
>Function registers (SFR's), specifically those that control the dma. You are
>supposed to be able to read/write to/from them just like memory. I can read
>them,
>but not write to them. Anyway, has anyone here used the V25 (the chip, I
>doubt if anyone has used jenlogix's sbc!). I can elaborate further if anyone
>thinks they have any suggestions.

I don't understand your problem, so long as you have the IDB set and
referenced properly you should just do normal reads & writes with the
internal data area.  Hmmm, I am not sure that I have used DMA on a V25,
but the Macro Services usually work fine for me.  I presume that the date
code on the chip you are using is at least '91, I don't remember being told
of any mask faults in more recent versions of the chip - certainly I have
seen very strange stuff happening on early edition, where macro services
and interrupts would collide.

Please explain your problem further, either here or by email to:
	amn@vms.brighton.ac.uk

Hope this helps,
Anthony Naggs
Software/Electronics Engineer                   P O Box 1080, Peacehaven
(and virus researcher)                          East Sussex  BN10 8PZ
Phone: +44 273 589701                           Great Britain
Email: (c/o Univ of Brighton) amn@vms.brighton.ac.uk  or  xa329@city.ac.uk