Search found 486 matches

by FARID
Thu Mar 26, 2020 2:39 pm
Forum: General Stuff
Topic: Meaning of "SUPER HIK"?
Replies: 4
Views: 153

Meaning of "SUPER HIK"?

When I was a child multicarts were common. I had two multicarts and I was fascinated by the art pictures on their plastic case : 1997 SUPER HIK 8 IN 1 EW-800 Gold 7 in 1 HIK AR456 Picture.jpg I have always wanted to know the meaning of the term HIK. Today I was googling and I saw this one by chance ...
by FARID
Tue Mar 24, 2020 12:24 pm
Forum: NES Hardware and Flash Equipment
Topic: SKROM Schematic?
Replies: 13
Views: 2909

Re: SKROM Schematic?

Fisher wrote:
Mon Mar 23, 2020 5:47 pm
Sorry for the necrobump, but could you please fix the missing images, Farid?
Thanks in advance.
check the first post :beer:
by FARID
Fri Feb 28, 2020 12:41 am
Forum: NES Hardware and Flash Equipment
Topic: Schematic for UM6561?
Replies: 30
Views: 22057

Re: Schematic for UM6561?

krzysiobal wrote:
Thu Feb 27, 2020 6:53 am
Nice wake-up after 2.5 years of inactivity, where have you been for that whole period of time?
I love NES forever and I will work on it again as soon as I become free.
For now I am busy with the university in order to improve my knowledge about analog electronics, it is really tough but sweet!
by FARID
Thu Feb 27, 2020 3:31 am
Forum: NES Hardware and Flash Equipment
Topic: Schematic for UM6561?
Replies: 30
Views: 22057

Re: Schematic for UM6561?

Last night I was digging google about UM6561 schematic and those Chinese docs , trying to find its original source. I found this page : https://zhuanlan.zhihu.com/p/59418044 which has an interesting reference at the end of the web page : 【1】刘泾(1996)。《用UM6561芯片的中英文电脑学习机的原理与维修》。《电子报合订本下册》,第292页 The na...
by FARID
Thu Sep 28, 2017 8:24 am
Forum: NES Hardware and Flash Equipment
Topic: Famiclone multicart - problems on power-up
Replies: 2
Views: 1505

Re: Famiclone multicart - problems on power-up

The diode seems to be inverted.
This works perfect for me :
by FARID
Mon Sep 11, 2017 12:31 pm
Forum: NES Hardware and Flash Equipment
Topic: EPROM LPT Programmer?
Replies: 33
Views: 9012

Re: LPT EPROM Reader?

I have tested it for a few times and it seems to work fine. 27C080 Read time : 40 Seconds 27C080 Write + Verify time : 40 + 60 Seconds OS : Windows XP When I started this project a few weeks ago, I didn't have any idea on how to make a programmer. I couldn't be able to do it without lidnariq help, t...
by FARID
Sun Sep 10, 2017 1:35 pm
Forum: NES Hardware and Flash Equipment
Topic: EPROM LPT Programmer?
Replies: 33
Views: 9012

Re: LPT EPROM Reader?

By using the bottom calculator, 120K seems to be a good value for R11 :
Vbe : 0 V
hFE : 110
Ic : 0.001 A
Vi : 3.3 V

By using the above calculator, 100K seems to be a good value for R14 :
Vbe : 0.7 V
Vce : 0.25 V
hFE : 110
RL : 4700
Vcc : 5 V
Vi : 3.3 V
by FARID
Sun Sep 10, 2017 11:52 am
Forum: NES Hardware and Flash Equipment
Topic: EPROM LPT Programmer?
Replies: 33
Views: 9012

Re: LPT EPROM Reader?

I calculated R11 manually and its value is 430K
But Transistor Base Resistor Calculator gives different value.
Where is my mistake?
by FARID
Sat Sep 09, 2017 11:33 am
Forum: NES Hardware and Flash Equipment
Topic: EPROM LPT Programmer?
Replies: 33
Views: 9012

Re: LPT EPROM Reader?

If you instead try to supply it with the output of the boost converter, then the 3.3V logic from the parallel port is no longer high enough to control the multiplexers. You were right 4053 doesn't work. I was thinking you'd use the NAND gate so that the hardware would automatically acknowledge both...
by FARID
Fri Sep 08, 2017 12:53 am
Forum: NES Hardware and Flash Equipment
Topic: EPROM LPT Programmer?
Replies: 33
Views: 9012

Re: LPT EPROM Reader?

Programming cycle #2 with ... hopefully $FF on the data bus? Therefore not actually a problem? So a bus conflict? Maybe it explains the strange writing behavior that I had when I used only 5v (not 6.5v) for writing. * Use /ASTROBE to increment the '4040 Awesome idea thanks So what do you think abou...
by FARID
Thu Sep 07, 2017 12:11 am
Forum: NES Hardware and Flash Equipment
Topic: EPROM LPT Programmer?
Replies: 33
Views: 9012

Re: LPT EPROM Reader?

It's definitely worth pointing out that you are already not using the EPP handshake . You are faking it by having the computer manually drive the WAIT line high and then low, which tricks the EPP hardware into thinking it's getting a handshake. Are you referring to this part of the code? : Out32 ( ...
by FARID
Wed Sep 06, 2017 10:12 pm
Forum: NES Hardware and Flash Equipment
Topic: EPROM LPT Programmer?
Replies: 33
Views: 9012

Re: LPT EPROM Reader?

If I want to use burn-verify-reburn-compare method I have to change the whole logic of the programmer, in that case even EPP handshake may become unusable. So how about this method : burn-compare At the start of the programming I ask the user about the condition of the EPROM which can be one of thes...
by FARID
Wed Sep 06, 2017 11:50 am
Forum: NES Hardware and Flash Equipment
Topic: EPROM LPT Programmer?
Replies: 33
Views: 9012

Re: LPT EPROM Reader?

I applied a 6.5v to VCC of EPROM and write was successful! A rapid programming algorithm is suggested in AT27C080 datasheet : Rapid programming algorithm A 50μs CE pulse width is used to program. The address is set to the first location. VCC is raised to 6.5V and OE/VPP is raised to 13.0V. Each addr...
by FARID
Wed Sep 06, 2017 2:03 am
Forum: NES Hardware and Flash Equipment
Topic: EPROM LPT Programmer?
Replies: 33
Views: 9012

Re: LPT EPROM Reader?

I made some modification to the schematic : VCC is only 5v USB (no 6.5v at all) Using a 47uF on VCC line made the read process more stable VPP 13v is generated by using MC34063 Instead of 33K pull down resistors I used 10K pull up resistors (same as Willem Programmer ) But unfortunately Writing EPRO...
by FARID
Sun Sep 03, 2017 7:55 am
Forum: NES Hardware and Flash Equipment
Topic: EPROM LPT Programmer?
Replies: 33
Views: 9012

Re: LPT EPROM Reader?

So I decided to use MC34063 to boost 5v to 12.75v, because it is inexpensive and small. I checked it's datasheet and in page 13 there is an example circuit for 12v --> 28v but I want 5v --> 12.75v so I have to recalculate the parts value. In page 14 there are some great and awesome formula for calcu...