Intel Microcontroller, 80C196NU, 8XC196NP manual Eport Block Diagram

Models: Microcontroller 80C196NU 8XC196NP

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I/O PORTS

Internal Bus

 

 

I/O MUX

 

EP_REG

 

Address MUX

I/O

 

VCC

 

 

(0)

 

 

 

 

 

 

 

 

EPC

CODE

 

 

Data

Extended Code Address

ADR

 

 

 

 

(from CPU)

 

 

 

 

 

(1)

 

Q1

64K

Force Page 00H

 

 

 

 

Extended Data Address

EDAR

DATA

 

 

I/O Pin

 

 

 

 

(from CPU)

 

 

 

 

Combinational

1M

 

 

 

 

Logic

 

 

 

 

 

 

 

Data/Address Control

 

 

MODE64 Control

(from Bus Controller)

 

 

 

 

 

Q2

(from CPU)

 

 

 

 

 

 

 

 

 

EP_MODE

 

 

 

 

Mode

EP_DIR

 

 

 

 

Direction

 

 

 

Sample

 

VSS

 

 

 

Latch

 

 

 

 

 

EP_PIN

Buffer

 

 

 

Q

D

 

 

 

 

LE

 

 

Read Port

 

 

 

 

 

 

 

 

PH1 Clock

 

NOTE: Shaded area is unique to the 80C196NU.

A3113-01

Figure 7-2. EPORT Block Diagram

If EP_MODE.x is set (address mode), the address multiplexer determines the address source. For an instruction fetch, the address multiplexer is set to the CODE input, which selects the extended program counter (EPC) as the address source. For a data fetch, or when there is no external bus activity, the address multiplexer is set to the DATA input, which selects the extended data address register (EDAR) as the address source.

The EDAR is loaded from two different sources, depending on whether the data access is extend- ed or nonextended. For extended data accesses, the data multiplexer is set to the 1-Mbyte mode input and EDAR is loaded with the extended address. For nonextended data accesses, the data multiplexer is set to the 64-Kbyte mode input and EDAR is loaded from EP_REG. The last value loaded remains in EDAR until the next data access. (Refer to “Fetching Code and Data in the 1- Mbyte and 64-Kbyte Modes” on page 5-23 for more information.)

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Intel Microcontroller, 80C196NU, 8XC196NP manual Eport Block Diagram