Got some new roms in. These are for my 8088/8086 the 6502 computer and C64 cartridges.
While I seldom had any problem writing to these, now I could not write one! Erasing didn´t give me an error?!?
henri@zspot:~/projects/wozmon8088/mon8086$ minipro -w mon8086.rom -p AT28C64
Found TL866II+ 04.2.129 (0x281)
Warning: Firmware is newer than expected.
Expected 04.2.128 (0x280)
Found 04.2.129 (0x281)
Erasing... 0.02Sec OK
Writing Code... 9.57Sec OK
Reading Code... 0.12Sec OK
Verification failed at address 0x0001: File=0xAA, Device=0xFF
Whenever you get this, check the markings of the chip!
Mine are AT28C64b !!!!!!!!!!!
Change your command accordingly. Another thing to watchout for is write protect, look at the commands
I really like GlaBios for my 8088, so today I got my Laser XT/3 8086 machine from the attic.
Mmm TWO ROM’s thats interesting
Looking futher in the schematics I found this. Apparantly there is a 8K ROM configured in a D0-D7 + D8-D15 setup. (16 bits)
Found a technical manual, this is a excerpt.
In Turbo XT, there are two 28-pin sockets for ROM, one of them is occupied by a 2764 which stored the BIOS (Basic Input Output System). The other empty socket is used to house a 32K ROM, such as the BASIC ROM
And about the XT/3 version which I have.
In Turbo XT /2 and Turbo XT /3, there are two 28-pin sockets for ROM, both of them are occupied by 2764 which stored the BIOS. The contents of the two 2764 are identical. One of them contribute the ODD Byte to the system and the other EVEN Byte. Together they support 16 Bit BIOS access.
This could be an interesting chat with Greg ..
Meanwhile i’m going to look how to split a rom into odd/even. Maybe i have to write a little python program for this.
Well, thats enough for today.
Lets fix my Cat S60 Flir phone, so i can track the hedgehog in our garden. (Battery replacement and powerbutton fix)
I fixed several phones before, (broken screen. touch not working). But I hate how some manufacturers build them.
I’ve build a logic probe a while ago. (Mentioned here)
Today I got the EIStar LP-1. Its just a cheap easy probe, but does the job. My version is only TTL and this one is TTL/CMOS (cmos is better when measuring arduino’s outputs) TTL – Logic 1 = 4.75 -> 5V CMOS – Logic 1 = more around the 3.3/3.7V
Only thing my version has which i’m missing is a pulse detector. One millisecond puls gets clocked into a latch and keeps a led on.
Schematic I found (some similarities can be seen with my version)
Started drawing a Cassette interface in Kicad. This so i can read back my old cassettes with programs. (And write some new stuff)
I’m planning to buy a small micro cassette player. With schematic below, I’m going to use it as save/load device. But also with the same player, I’m going to convert the tape to a wave file, and try to decode the program using python.
While I’m at it, reading the old manuals, a RS-232 interface would be nice also!
While working on my game, i had to come up with some solutions i could not find an answer for on the internet.
I’m not going to post every little detail of my game on this blog, my main reason is sharing my experiences and solutions.
16 Switches on a Wemos Arduino. While push buttons are easier to connect, I needed ON/OFF switches. Push buttons are easy, there is only one active, so 4 enable lines and 4 scan lines and you’re golden. 16 Switches can be enabled all at the same time. So you need some extra components to get a good result (0-65535)
Above schematic works, you need 4x 1k Pull-up resistors and 16 diodes. I used 1N4007
CONTROLLING 24V using Arduino and a buck convertor
Next problem, i’m using some elevator buttons for a project. These have build-in leds but run at 24V. I only have 5V from the Arduino. Regular leds you can connect directly to the Arduino using a 220ohm resistor. So i used a Buck-Step-Up-Convertor. This little module converts 5V to 24V. (You can control the output voltage using a variable resistor) To control the lamp/leds i used a PN2222a transistor to switch the lights on/off using a pin of the Arduino.