IO Board completed and installed; question about uptime word

Hardware
1

Hello, I’ve finished the IO board and I’ve installed it. I can use the LED control words (vslights, etc) and they seem to work, so at least part of the board is functioning! However, I cannot get “uptime” to work. As I understand it, It should use one of the timers in the 6522 to give an uptime for the system.

It’s defined as : uptime time @ 2 time + @ 200 um/mod s>d 60 um/mod s>d 60 um/mod cr . ." h " . ." m " . ." ," 2/ . ." s" cr ;

In my case, uptime always returns something like: -1 h 59 m 59 ,-12076 s

When I do time ., it returns 8, which I assume is $08 in the zero page. I’ve looked at the data in the zero page, but I don’t see any change, which makes me wonder if the timer on the 6522 is not being started? Is this a hardware problem on my side? Not sure what to do next.

Does anyone have any suggestions about how to get uptime to work?

2

Hi Ben,
Make sure that the timer code is included in the main.s file, it should look like this:
.include "drivers/timer.s"

Otherwise, you can try and send some debug information via serial in the IRQ handler, to see if if the timer interrupt is called.

3

Hi Jonathan,

Thanks for the reply - I can see that the timer.s code is in the planck-listing.txt, and I’ve also located it in the code on the ROM (it’s at $22D to $24D), so that doesn’t seem to be the problem. I will keep digging.

I also have not had any luck with the PS/2 keyboard port yet. To be sure I’m understanding how it works, the system should accept input from the PS/2 port, even if I’m connected via serial to my machine via minicom, correct?

4

You have to activate the PS/2 keyboard by uncommenting the .include "drivers/ps2.inc" line in main.s, which you have probably done already. If that is done, you should at least get a line printed out that says “Detecting keyboard”. In my experience modern “PS/2” keyboards do not work reliably though…

To answer your question, yes you can have both the keyboard and the serial port as inputs.

5

SOLVED: Uptime word and timer initialization

Hello,

The timer_init routine was commented out at line 150 of main.s. After uncommenting and recompiling the ROM, uptime works as expected.

Best wishes, Ben

150 .ifdef timer_init
151     ; bjc uncommented below
152     jsr timer_init
153 .endif
6

Oops sorry about that, I was probably testing something else and commited that commented line…