gil@jts.com (gil) (09/12/90)
I am currently working with the Motorola 68705 uP and have noticed the absence of stack operation instructions (push/pop etc.). Does anyone have any ideas about gaining access to the stack pointer, i.e. is it shadowed in RAM somewhere or are there any undocumented op-codes to do this? +-----------------------------+-------------------------------------------+ | Gil Hauer, Tech Noir Inc. | gil@jtsv16.jts.com | | Toronto +1 416 653-8276 | or: uunet!jtsv16!gil | +-----------------------------+-------------------------------------------+ Opinions expressed herein are solely my own and any resemblance to those of my employers or clients (living or dead) is purely coincidental. -- +-----------------------------+-------------------------------------------+ | Gil Hauer, Tech Noir Inc. | gil@jtsv16.jts.com | | Toronto +1 416 653-8276 | or: uunet!jtsv16!gil | +-----------------------------+-------------------------------------------+
john@qip.UUCP (John Moore) (09/14/90)
In article <1990Sep12.145331.6233@jts.com> gil@jts.com (gil) writes:
]
]I am currently working with the Motorola 68705 uP and have noticed the
]absence of stack operation instructions (push/pop etc.).
]
]Does anyone have any ideas about gaining access to the stack pointer,
]i.e. is it shadowed in RAM somewhere or are there any undocumented
]op-codes to do this?
As far as I know, there is NO way to get access to the stack pointer.
It is not saved on interrupts, and there is no instruction to
store it.
--
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Opinion: Support ALL of the bill of rights, INCLUDING the 2nd amendment!zimmer@calvin.tmc.edu (Andrew Zimmerman) (09/14/90)
In article <1990Sep12.145331.6233@jts.com> gil@jts.com (gil) writes: > >I am currently working with the Motorola 68705 uP and have noticed the >absence of stack operation instructions (push/pop etc.). > >Does anyone have any ideas about gaining access to the stack pointer, >i.e. is it shadowed in RAM somewhere or are there any undocumented >op-codes to do this? > >+-----------------------------+-------------------------------------------+ >| Gil Hauer, Tech Noir Inc. | gil@jtsv16.jts.com | >| Toronto +1 416 653-8276 | or: uunet!jtsv16!gil | >+-----------------------------+-------------------------------------------+ This is going to be a gross hack, you might not want to read any further. The only way that I can see to do this is to have a subroutine that you call, and then set the x register to ff and move back through the stack looking for the address of the called subroutine. This might not work if the CC's can be set such that they could be the same as the subroutine address, I haven't checked into that yet. I am having the exact same problem in writing a small monitor for the 68h805. Okay, I'm not writing the monitor, I'm stealing parts of the monitor fro the 05 and the evaluation version of the 805PA1. Currently, my version of the monitor has the Dump, load, Go, and the Bulk erase command. I am currently adding the register commands. The monitor takes up the B-array, and the bulk erase only erases the A-array. If anyone wants what I have, I will make it available via anon-ftp. Does anyone know if the Vpp charge pump bit has to be set on the prototype version of the 805 which needs 19.75 volts? For those who need this voltage, the TL497 works great. Using that chip and the MAX232, all you need is +5 and Gnd. Andrew zimmer@calvin.stanford.edu PS. I wish all companies had the same customer relationship that Motorola has. They are extremely helpful.
zimmer@calvin.tmc.edu (Andrew Zimmerman) (09/14/90)
Does anyone know the programming algorithm for the PALCE16V8 made by AMD? For those that don't know, the PALCE16V8 are Electrically eraseable programable array logic. At a price of $1.99 at Fry's, they look like they would be great for both the home hobbiest and for schools. Unfortunately the cheapest programmer I have found is about $900. A call to AMD did get me a data book, but no programming info. I would like to be able to program the devices in circuit if possible. Thanks for any help, Andrew zimmer@calvin.stanford.edu