Beeper for SC126

[Pavel Žampach]

SC126 has ability to switch Flash ROMs by bit 1 of internal port ($0C), but in this time there is no software using this feature. This option can be used for enabling simple beeper for SC126.

Hardware
is very simple. I've connected small (11 mm) piezo buzzer directly to edge pins of P9 header.

Software
RomWBW 3.01
In customization file (f.e. SCZ180_126_CUST.ASM) add line

SPKENABLE    .SET    TRUE

and in file SPK.ASM change line

    XOR    %00000100        ; Flip bit 2.
to
  XOR    %00000010        ; Flip bit 1.

Unfortunatelly in this issue the beeper driver is not accessible for applications and only beeps at boot time (-:


RomWBW 3.1 (preview)
In customization file (f.e. SCZ180_126_CUST.ASM) add line

SPKENABLE    .SET    TRUE

and in file SPK.ASM change line

SP_RTCIOMSK    .EQU    00000100B
to
SP_RTCIOMSK    .EQU    00000010B

In this issue the beeper driver is accessible for applications (new HBIOS functions), but duration of tone is fixed to 1 sec.

[Steve Cousins]

Interesting use of the Flash ROM select bit. Very imaginative. As far as I'm aware, you are correct, there is no software available to use this bit for its intended purpose.

This output bit is intended to allow both 512k byte Flash chips to be available at the same time using suitable software to select the required bank in real-time. This potentially allows SC126 to have a 1M byte firmware system in Flash (rather than two totally independent 512k byte firmware systems).

Steve

[Bob Dunlop]

Not quite the intended purpose but I use the bit to select a second bank of 512K RAM in the second Flash slot. (You need to swap two pins on the RAM chip to fit the Flash socket.)

I believe my patch to detect and enable the second RAM bank is now in the FUZIX source, so once booted the system runs with a full 1MB of RAM.

[Alan Cox]

On Sun, 12 Sept 2021 at 14:16, Bob Dunlop <bob.d...@xyzzy.org.uk> wrote:

Not quite the intended purpose but I use the bit to select a second bank of 512K RAM in the second Flash slot. (You need to swap two pins on the RAM chip to fit the Flash socket.)

I believe my patch to detect and enable the second RAM bank is now in the FUZIX source, so once booted the system runs with a full 1MB of RAM.

Fuzix does use this feature, but if you have it jumpered directly to a specific ROM then apart from a click or two at boot up all will be fine if it's used as a buzzer.

Alan