KIM Uno Digital Clock

In addition to this clock program, now there is a new application you can add to your KIM Uno, an Enigma Z Machine Simulator.

Follow the link below to learn more:

https://hackaday.io/project/18644-mystery-6502-program-for-the-kim-uno-1kbchallenge

This project was submitted to a reddit unconventional clock contest. Two entries will win. One will be decided by popular vote, the other one by a panel of judges.

https://www.reddit.com/r/diyelectronics/comments/4dh0x8/voting_thread_beginner_challenge_an/

The routine from 424 to 42D delays for a second while keeping the display alive by calling the KIM ROM routine to display the value of cells F9,FA,FB on the display. On my KIM, the value of 45 was found to be the best, 46 is too slow, 44 is too fast.

If you need to adjust yours, hold the [RS] key down for more than 1 second until the display flashes, this indicates that the write protection to the EEPROM is off. then enter [AD] 425 [DA] and type your new two digit delay value.

To have a more precise delay, a nested loop containing nops would need to be placed inside the existing loop. This would increase the byte count though.

The time display routine would look like this. To adjust the time, change the LDA $44 and LDA $90 lines. The first one is a coarse and the second a fine adjustment.

LDA #$44
STA *$28
L1

JSR $1F1F

LDA #$90
STA *$27
L2
NOP
DEC *$27
BNE L2

DEC *$28
BNE L1
JMP START

* = $0400
0400 START  
0400        SED             F8
0401        CLC             18
0402        LDX #$00        A2 00
0404        LDA #$01        A9 01
0406        STA *$29        85 29
0408 NEXTD  
0408        LDY #$00        A0 00
040A        LDA *$29        A5 29
040C        ADC *$24,X      75 24
040E        STA *$24,X      95 24
0410        CMP CARRYT,X    DD 32 04
0413        BEQ CONTIN      F0 06
0415        LDY *$24,X      B4 24
0417        LDA #$00        A9 00
0419        STA *$29        85 29
041B CONTIN 
041B        STY *$24,X      94 24
041D        STY *$F9,X      94 F9
041F        INX             E8
0420        CPX #$03        E0 03
0422        BNE NEXTD       D0 E4

0424        LDA #$45        A9 45
0426        STA *$28        85 28
0428 L1     

0428        JSR $1F1F       20 1F 1F

042B        DEC *$28        C6 28
042D        BNE L1          D0 F9

042F        JMP START       4C 00 04


0432 CARRYT 
0432 .BYTE $60              60
0433 .BYTE $60              60
0434 .BYTE $24              24