A2SCSI-A03 - Apple II SCSI card cloneSubmitted by GG on Fri, 07/22/2022 - 01:59
A2SCSI-A02 - Apple II SCSI card cloneSubmitted by GG on Fri, 06/24/2022 - 19:34
A new version of this project is available here
The Apple II SCSI card from 1986 was one of the first interface cards to attach a Hard Disk Drive to the Apple II line of computers. A2SCSI is a clone of the last revision (rev.C) of the card with a few enhancements to improve compatibility with modern SCSI drives.
M100ROM - 27C256 adapter for Tandy Model 100Submitted by GG on Tue, 05/17/2022 - 16:47
The Tandy TRS-80 model 100/102 and 200 provide a ROM socket to add built in programs to the machine. To make inserting and replacing the ROM more user friendly the designers choose to use a custom chip socket (Molex series 78805) with 700mils pitch. The Molex carriers that mate with the sockets have been out of production for many years and are nowadays impossible to obtain.
6502 C Compilers ComparisonSubmitted by GG on Sat, 03/12/2022 - 01:11
C is our favorite language as it provides reasonably high level constructs while maintaining very good performance. The majority of the code we write for for both vintage computers and microcontrollers computers is in C. In this article we compare several C compiler for the 6502 to understand the performance and limitations of each.
SDCC 4.2.0 ReleasedSubmitted by GG on Tue, 03/08/2022 - 13:47
A new release of SDCC, the portable optimizing compiler for STM8, MCS-51, DS390, HC08, S08, Z80, Z180, Rabbit, SM83, eZ80 in Z80 mode, Z80N, TLCS-90, 6502, Padauk and PIC microprocessors is now available. Sources, documentation and binaries for GNU/Linux amd64, Windows amd64, macOS amd64 and Windows x86 are available.
GS2HD - Apple IIgs RGB to HDTV Component AdapterSubmitted by GG on Thu, 01/13/2022 - 15:25
The apple IIgs, like many computers from the 80's and early 90's, has a analog RGB output at a 15KHz horizontal frequency (same as NTSC/PAL). The majority of modern monitors and TVs will not sync to anything below 31.5KHz on their VGA input. If you have a TV with a SCART connector it is possible to wire the RGB directly to the TV. Most TVs in USA, however, use the YPbPr component instead of SCART making a direct connection not possible.
SDCC 6502 supportSubmitted by GG on Sun, 01/09/2022 - 10:35
Recently we have been working with the SDCC team to include 6502 support in the next release of SDCC. The port is largely based on the excellent work from Steve Hugg at 8-bit workshop. The port passes all the tests in the regression suite and it will be included in the upcoming 4.2.0 release.
M10MEM - 8KB SRAM Module for Tandy Model 100Submitted by GG on Wed, 11/03/2021 - 20:02
Being nostalgic for the birth of laptop computers we recently acquired an Olivetti M10. The M10, like many of the KC-85 derivatives like the Tandy TRS-80 Model 100 and the NEC PC8201A, uses custom modules for their system RAM. These modules contained four 2Kx8 SMD SRAMs mounted on a ceramic substrate with a non standard DIP footprint. Needless to say, these modules have become increasingly hard to find.
E2R16v2.2 - 27C400/800/160/322 programming adapter for Minipro TL866Submitted by GG on Thu, 09/23/2021 - 17:39
The Minipro TL866 is very popular among hobbyist because of its low price and ease of use. Its list of supported chips is however somewhat limited compared to more expensive professional programmers. The E2R16v2 adapter adds support for the ROM pinout compatible EPROM of the 27C400/800/160 and C322 series.