Programmable Peripheral Interface
&
Direct Memory Access
Dr. Md. Rejvi Kaysir
Programmable Interface Device
• Programmable interface device is designed to perform various I/O
functions. Such a device can be setup to perform specific functions by
writing an instruction (instructions) in its internal register, called
control register.
The 8155: Multipurpose Programmable device
The 8155: Programmable I/O Ports
• I/O ports can be configured by
Writing an appropriate control
Word.
8255 Programmable Peripheral Interface
Modes:
Control word
Format for I/O Mode
Problems:
DMA (Direct Memory Access)
• Please see the Ref. Book Page- 514 & 515
• Please focus on the topics that I said in the class.