Building a CP/M System Disk To avoid rewriting the assembler codes for ccp, bdos and cbios so that they can co-exist in the same file. I can append the i8hex files and remove the "end of file markers". To make the hex file more readable I have changed...
Ok, now it is kind of proven that binary CPLD (or FPGA) may implement ternary logic, but how we can integrate it with "true" ternary components, especially when CPLD is 3.3V and TRIMUXes are -5V and +5V? Answer is DG403 chips may do the job: Because...
Operating under the current assumption that RAM is 32 KiB banked at address 0000-7fff, with the first 256 bytes masked off by special function registers and internal SRAM, some other code sections of interest were found. E.g.:ED00 loc_ED00: ED00...
Fortunately most of the NASA documents are available. They can be found on-line at https://www.ibiblio.org/apollo/Documents/ The following documents are what I leaned heavily on in gaining an understanding of how this computer...
Before I began the layout of the DDL4-CPU, I came up with an initial Instruction Set Architecture (ISA) for the design. It went through several revisions as I was designing the boards and refined the components. Here at the last minute as I am...
The 5.21E ROM works file with the current board, but the 7.11A ROM uses a different pin for the vertical sync signal. This can be fixed, but then the 5.21E ROM results in no display. Rather than fixing the hardware (with a jumper to be changed when the...
Revisiting the RAM signature stamping knowing what I know now, I can better see what's going on and record that knowledge. The RAM stamping routine now looks like this:F723 ; stamp 'ram valid signature' on RAM page 0 and 3 F723 stampRAMsignature_F723:...
Switching over to an ARM based solution is much better than an AVR+RTC chipset solution. Been looking at the STM32F030 chip and it is a perfect fit for this application! It has the following very desirable characteristics:32.768kHz oscillator on-chip....
I took a perfboard and soldered up power and the data/address busses of the MCU, SRAM, NVRAM and the address bus latch.I did't really care about the exact order of the bits when wiring them up, I just went for the easiest layout. I'm not really sure...
I think about Terminal-BASIC based programmable calculator, like MK-90 I am planning to use Arduino DUE, TFT screen schield and custom matrix keyboard of40-64 keys.Does anybody know, if this shield is compatible with arduino DUE?Actually, I'v just tried...
The end goal for the Autodro is a complete monitoring system for under $10. This means that cheaper, simpler, less accurate sensors are needed. I've started with a simple EC sensor, and am hoping to design something around $1.So far, I've created a sensor...
At last, I found a bit in EC RAM that is used to enable EC ACPI, so ACPI is working now. I copied the ASL code from vendor DSDT, and now battery, AC, and lid status change can be detected by OS now.https://review.coreboot.org/#/c/19072/
I also wanted to sniff the communication between the micro controller and radio IC, but couldn't get the case of the remote control open. At the next opportunity I brought the Mi-Light Wi-Fi controller with me and got that open more or less easily:Inside...
I just got the pH portion of the circuit working. There actually wasn't anything wrong with the circuit. It turns out that the probe that I was initially was using was bad. I tried a different brand and it worked perfectly. The working probe is listed...