Tag: EEPROM

Software development for the 805x series

While working with my now working 8052 SBC, I spent some time testing with the BASIC-52 (v1.31) program.  One of the things I noticed is that the default value for the XTAL variable is set for 11.0592 MHz.  In looking at the source code, which is written in assembly, I found where the default value … Continue reading Software development for the 805x series

Slow EEPROM reduces maximum oscillator frequency

In my previous post, I had written about having difficulties with the AT89C52's oscillator being unstable and how I cured that issue. Once I had achieved a stable oscillator, I increased the clock to 20 MHz.  All seemed to work properly.  I was able to write a BASIC program and save it to EEPROM using … Continue reading Slow EEPROM reduces maximum oscillator frequency

Oscillator functioning properly – All looks well

In one of my previous posts, I had written that during testing, I found the AT89C52's oscillator to be unstable and unreliable at 11.0592 MHz.  I had also found that the RESET signal going to the AT89C52 via the GAL22V10 was also "lingering" mid-rail before returning low, which was causing intermittent failures to reset the … Continue reading Oscillator functioning properly – All looks well

AT89C52 arrival and more hardware/software testing

The newly purchased AT89C52's from a different vendor arrived in relatively short order.  The original order from a Chinese eBay vendor still have not arrived (as of yet). That seller has issued a refund but from prior attempts to order AT89C52's from what seemed to be different sources, has been met on a few occasions … Continue reading AT89C52 arrival and more hardware/software testing

PCB Hardware Testing – diagnostics and remedy

The last few days I have been investigating the reason(s) why my hardware does not seem to work.  There are a few software "modules" that are supposed to run "out of the box" via that particular author's HEX file build.  Thus far, I have downloaded and attempted to run; PAULMON2.1, MCS-51 BASIC (v1.1, v1.2 and … Continue reading PCB Hardware Testing – diagnostics and remedy

PCB testing – No joy so far…

Since I built up the single PCB, I have started testing the hardware.  Of course, the hardware on this project is useless unless it has software to make it do something.  I first noticed that the 8052AH, which I am using until the AT89S52's arrive, was running a bit warmer than I thought it should. … Continue reading PCB testing – No joy so far…

Arrival of PCB’s.

Arrival of PCB’s.

Today, after 13 days of shipping time, the PCB's for this project arrived.  They look good and I have no complaints about the quality of the boards.  I think YOUPCB.COM did a great job on these boards and I would use them again for small quantities.  The only issue I had was in the tracking number.  I … Continue reading Arrival of PCB’s.