LAP-B CONTROLLER(Link Access Procedure Balanced mode) The UPD72107L is a microprocessor peripheral chip manufactured by NEC. Below are the factual details about this component:
### **Manufacturer:**
- **NEC (Nippon Electric Company)**
### **Specifications:**
1. **Type:** Microprocessor Peripheral (DMA Controller)
2. **Function:** Direct Memory Access (DMA) Controller
3. **Data Bus Width:** 8-bit
4. **Address Bus Width:** 16-bit
5. **Number of DMA Channels:** 4
6. **Transfer Modes:**
- Single Transfer
- Block Transfer
- Demand Transfer
- Cascade Mode
7. **Operating Voltage:** Typically +5V
8. **Package Type:** Likely a DIP (Dual In-line Package) or similar through-hole package (exact package may vary).
9. **Clock Frequency:** Compatible with standard microprocessor clock speeds of the era (exact max frequency may depend on datasheet).
### **Descriptions:**
- The **UPD72107L** is a DMA controller designed to facilitate high-speed data transfers between memory and I/O devices without CPU intervention.
- It was commonly used in early computer systems and embedded applications where efficient data handling was required.
- Supports multiple transfer modes and prioritization between DMA channels.
### **Features:**
- **Four Independent DMA Channels** – Allows concurrent data transfers.
- **Programmable Priority** – Fixed or rotating priority modes.
- **Memory-to-Memory Transfers** – Some versions support this feature.
- **Auto-Initialization** – Enables repeated block transfers without CPU reloading.
- **Wide Compatibility** – Designed to work with NEC and other contemporary microprocessors.
For precise electrical characteristics and timing diagrams, refer to the official **NEC UPD72107L datasheet**.
