VLSI VL82C147

For the VLSI VL82C147 I/O chip,

the Ir link can be realized with the

following connections:

Connect IROUT pin 66 of the

VL82C147 to the I/O side of R1/CX2

labeled TXD on the HSDL-1100

diagram.

Connect SIRIN pin 67 of the

VL82C147 to RXD-A (pin 8 of the

HSDL-1100).

Connect FIRIN pin 65 of the

VL82C147 to RXD-B (pin 5 of the

HSDL-1100).

SMC FDC37C957

For the SMC FDC37C957 I/O chip,

the Ir link can be realized with the

following connections:

Connect IRTX pin 204 of the

FDC37C957 to the 0.1 mF capacitor

connected to R1/CX2 of the HSDL-

1100 diagram.

Connect IRRX pin 203 of the

FDC37C957 to RXD-A (pin 8 of the

HSDL-1100).

HSDL-1100

RXD-A RXD-B

8 7 5

R1 CX2

38 39 37

PC87108

IRTX IRSLO/IRRX2 IRRX1

HSDL-1100

RXD-A RXD-B

8 7 5

R1 CX2

67 66 65

VL82C147

IROUT FIRIN SIRIN

Connect IRMODE pin 190 of the

FDC37C957 to RXD-B (pin 5 of the

HSDL-1100).

CX3 must be 1000 pF in the

application circuit (other I/O chips

use 4700 pF).

Note that the 0.1 mF capacitor

connected to the transmit line is

necessary since the SMC I/O chip

IRTX pin could be left in a logic

high state for an indeterminate

period of time. Connection of the

IRTX directly to R1/CX2 would

damage the HSDL-1100’s LED if

the IRTX line was left in the logic

high state.