Problem with H4 not booting (zChris's board)

[rubber_jonnie]

@rubber_jonnie I'd initially thought rom but had forgotten about the LS11

I specifically remember because I initially didn't install it as I misunderstood the requirements. Then I had major problems and had to add a bodge wire to fix.

[zChris]

You need to check that line I highlighted.. but check it on the jumper on your scope and keep pressing reset to see if it changes.

Nothing happens when i press reset on the jumper, it is constantly on 5V. Should it be that?

/zChris

[exxos]

Nothing happens when i press reset on the jumper, it is constantly on 5V. Should it be that?

Nope, what about reset pin on cpu ?

[zChris]

Reset (Pin 18) goes to low (0v) when reset button is pressed and high (5.2v) when it is released.

/zChris

[zChris]

Measuring when the reset button is pressed in i got 0.2 on Pin 23,17,4,3,2. When releasing reset pin 17,4,3,2 went from 0 -> 5V and then down to 0 again. Nothing changed on Pin 23.

/zChrus

[PhilC]

@zChris for clarity, you are checking at a dip socket not the plcc one for the cpu?

[zChris]

Have i done the calculations correctly here.

6 squares from top to top = 6x20ns=120ns=0.00000012s

Then 1/0.00000012 = 8333333.33333roughly 8.3Mhz ?

DSC_1374.JPG (259.84 KiB) Viewed 2677 times

/zChris

[zChris]

@zChris for clarity, you are checking at a dip socket not the plcc one for the cpu?

Im checking in the expansion port. Thats wrong?

/zChris

[PhilC]

@zChris no that's fine, just checking so everyone knew.

[exxos]

Have i done the calculations correctly here.

Just press the measure button and select frequency.. then it will tell you the frequency..