Post by mirkosoft on Oct 9, 2016 20:06:04 GMT
Hi!
I was searching for some booting options and found also power-on messages and others.
In case of power-on messages I found something which I found not on C64, Plus/4 & C16, C65, even M65.
Commodore 128 can output power-on message without loosing Basic program, even without touching content of inactive screen - and in two ways:
SYS16384 - shows power-on message with all extensions if are placed in text (like JiffyDOS...)
SYS16795 - shows default power-on message - untouched text
...
When I found this I began search how to call SuperCPU boot action - in VIC screen it is animation, in VDC screen it's graphic:
But these "messages" are shown only at power-on - no after reset and also when is SCPU turned off, by turning it on and reset it shows it too. No other way.
If it shows at power-on and not at reset - what other in reset routine is not? I know that's stupid Q, but look at:
- at power-on is initialized Z80, when is CP/M disk found not it switches to 8502
- Z80 starts at address $0000
- after reset is also initialized - again CP/M disk check
- when is connected SCPU and turned on, Z80 init there must to be - no any add-on hardware can change computer - and if is CP/M disk found it tries to boot in Z80 mode, but fails to MLM 'cause Z80 cannot work with SCPU together (this was reason why I bought also CP/M cartridge - have Z80 available)
- so, when is SCPU activated it performs "message" above - no matter if it is by power-on or reset - at activation...
- 65816 has instruction STP - puts 65816 into silicon heaven and only reset or power-off then on it makes active again, but "message" appears only at power-on
How to simulate power-on instead reset - action like attempt to any CPU pin stimulation or so? Also I mean - if will be possible this, then will be possible GO128 like on C65/M65...
Each idea is welcome.
Miro
I was searching for some booting options and found also power-on messages and others.
In case of power-on messages I found something which I found not on C64, Plus/4 & C16, C65, even M65.
Commodore 128 can output power-on message without loosing Basic program, even without touching content of inactive screen - and in two ways:
SYS16384 - shows power-on message with all extensions if are placed in text (like JiffyDOS...)
SYS16795 - shows default power-on message - untouched text
...
When I found this I began search how to call SuperCPU boot action - in VIC screen it is animation, in VDC screen it's graphic:
But these "messages" are shown only at power-on - no after reset and also when is SCPU turned off, by turning it on and reset it shows it too. No other way.
If it shows at power-on and not at reset - what other in reset routine is not? I know that's stupid Q, but look at:
- at power-on is initialized Z80, when is CP/M disk found not it switches to 8502
- Z80 starts at address $0000
- after reset is also initialized - again CP/M disk check
- when is connected SCPU and turned on, Z80 init there must to be - no any add-on hardware can change computer - and if is CP/M disk found it tries to boot in Z80 mode, but fails to MLM 'cause Z80 cannot work with SCPU together (this was reason why I bought also CP/M cartridge - have Z80 available)
- so, when is SCPU activated it performs "message" above - no matter if it is by power-on or reset - at activation...
- 65816 has instruction STP - puts 65816 into silicon heaven and only reset or power-off then on it makes active again, but "message" appears only at power-on
How to simulate power-on instead reset - action like attempt to any CPU pin stimulation or so? Also I mean - if will be possible this, then will be possible GO128 like on C65/M65...
Each idea is welcome.
Miro