W78IRD2 datasheet(5/76 Pages) ETC2

5 / 76 page

W78IRD2

Publication Release Date: October 2, 2006

- 5 -

Revision A7

PIN DESCRIPTION

SYMBOL

TYPE*

DESCRIPTIONS

EXTERNAL ACCESS ENABLE: This pin forces the processor to execute

instructions in external ROM. The ROM address and data are not presented on

the bus if the EA pin is high.

PSEN

O H

PROGRAM STORE ENABLE: PSEN indicates external ROM data is on the

Port 0 address/data bus. If internal ROM is accessed, no PSEN strobe signal

is present on this pin.

ALE

O H

ADDRESS LATCH ENABLE: ALE is used to enable the address latch that

separates the address from the data on Port 0. ALE runs at 1/6th of the

oscillator frequency.

RST

I L

RESET: If this pin is set high for two machine cycles while the oscillator is

running, the W78IRD2 is reset.

XTAL1

CRYSTAL 1: Crystal oscillator input or external clock input.

XTAL2

CRYSTAL 2: Crystal oscillator output.

VSS

GROUND: ground potential.

VDD

POWER SUPPLY: Supply voltage for operation.

P0.0

− P0.7 I/O D

PORT 0: 8-bit, bi-directional I/O port, the same as that of the standard 80C52

Port 0 has internal pull-up resisters enabled by software.

P1.0

− P1.7 I/O H PORT 1: 8-bit, bi-directional I/O port, the same as that of the standard 80C52.

P2.0

− P2.7 I/O H

PORT 2: 8-bit, bi-directional I/O port with internal pull-ups. This port also

provides the upper address bits when accessing external memory.

P3.0

− P3.7 I/O H PORT 3: 8-bit, bi-directional I/O port, the same as that of the standard 80C52.

P4.0

− P4.3 I/O H PORT 4: 4-bit, bi-directional I/O port with chip-select functions.

* Note: TYPE I: input, O: output, I/O: bi-directional, H: pull-high, L: pull-low, D: open drain

W78IRD2 Datasheet(PDF) 5 Page - List of Unclassifed Manufacturers

W78IRD2 Datasheet(HTML) 5 Page - List of Unclassifed Manufacturers

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76

Datasheet Download

Link URL