H8-4 MULTI I/O *NOT TESTED
H8-4 MULTI I/O INTERFACE V1.0
H8-4 MULTI I/O
Supports 4X 16C550 with 20mA loop and USB Serial ports, I2C Buss, DSRTC, OLED Display, qwiic Interface, USB HDOS printer, USB VDIP1 Interface,
Schematics V1.0
Schematics V1.1
Gerber_Files V1.1
Development_Files V1.1
Board_Side_1_View_Print
Board_Side_1_View
iBOM V1.1
X-RAY View v1.1
GAL-IO_DECODER (New May 24, 2026)
OLED HDOS Programs
DSRTC HDOS Program
HDOS USB Printer Files:
lpusb.asm main source file for lpusb driver. This started with Glenn’s disassembly of the parallel port driver.
Uob.acm unpack octal byte acm from the HDOS tools disk that I modified slightly
Usbdvd.acm XTEXT file that has all of the VDIP-specific USB code
Lp.dvd driver that should already be SET for your VDIP port 261Q (SET LP: HELP will display the current port setting)
Mxescp.txt sample text file with embedded ESC-P print control codes
