Low Voltage BS1

Archiver

Greetings!

I've been studying the BS1 schematics and some datasheets.

The PIC microcontroller('Interpreter chip') is able to run at 2.5V, and the
datasheets I managed to find about the type of serial EEPROM that is used
also indicates that it can run at 2.5V.(May be wrong, because I'm not
certain about supplier)

If both those chips can run at 2.5V, is there any reason that it shouldn't
work if I replace the Reset circuit with one that activates at below 2.5V(or
just disables it) and connects a 3V button cell to the VDD pin?
(Then I can always connect a 9V battery to the VIN pin hen I need to program
it)

:-)
Trygve

Archiver

Trygve,

I don't see any problem with your plan to operate the BS1 at 3 volts.
If the power supply is applied quickly and reliably, the chip will
operate just fine without the reset chip. In fact, the BS1 rev D
never did have a separate reset chip.

Well, the thing to do is hook it up and see if it works. I just now
took a BS1 rev D, version 1.4, and verified that it does in fact work
fine from a lithium cell at 3.0 volts, and it drew 0.6 milliamp. The
lithium cell + was connected to the output of the LM2936 regulator
(Vdd). The same circuit operating from a 9 volt battery connected to
Vin drew 1.5 milliamp.

-- Tracy


>Greetings!
>I've been studying the BS1 schematics and some datasheets.
>The PIC microcontroller('Interpreter chip') is able to run at 2.5V, and the
>datasheets I managed to find about the type of serial EEPROM that is used
>also indicates that it can run at 2.5V.(May be wrong, because I'm not
>certain about supplier)
>If both those chips can run at 2.5V, is there any reason that it shouldn't
>work if I replace the Reset circuit with one that activates at below 2.5V(or
>just disables it) and connects a 3V button cell to the VDD pin?
>(Then I can always connect a 9V battery to the VIN pin hen I need to program
>it)
>
>:-)
>Trygve