OptoOut8-I2C

Eight Channel Optically Isolated Output Card with I2C bus

Features

• Eight optically-isolated output channels on card
  • (8) 4N25 optoisolators
• MCP23008 I2C Parallel I/O
  • I2C (Two Wire interface)
  • 100/400 KHZ operation
  • 25mA sink/source capability per I/O
  • Jumper selectable 2.2K Ohm terminators
  • 3-bit address (Jumper selectable) - Up to 8 boards
  • Single 4-pin host interface connector (Ground, Power, Clock, Data)
• 24LC024 Personality EEPROM
  • Write protect jumper
• 5V operation
• Compatible with Arduino, Raspberry Pi, BeagleBone Black
• DB-25F connector for rugged applications
• 95x95mm form factor
• (4) 6-32 mounting holes - one on each corner

MCP23008 Block Diagram

Optocoupler Performance

• 4N25 Optocoupler
• DC Current Transfer Ratio

• Current Transfer ratio curve

• LED Current vs voltage

• Output transistor capacitance

• Switching Time

Opto Characteristics				
Current Transfer Ratio	10.00%	min		
Vcc	5	V	3.3	V
Vf(Diode)	1.25	V	1.25	V
Res series LED	330	Ohms	330	Ohms
If (LED)	0.0113636364	A	0.0062121212	A
CTR	0.6	A/A	0.2	A/A
Current Trans CE	0.0068181818	A	0.0012424242	A
Res (load pullup)	4700	Ohms	4700	Ohms
Vce	0.2	V	0.2	V
V load side	5	V	5	V
Iload	0.0010212766		0.0010212766	

Connectors

J1 - Power

J2-J3 - I2C

J4 - I2C Address Select Jumpers

J5 - I2C Termination Jumpers

J6 - Card Present/Interrupt

1. GND
2. INT
3. CP - Card present (pulled low)

J7 - I/O connector

DB-25 Female

OptoOut	OptoOut	DB25RIB	DIGIO32	DB37RIB		OptoOut	OptoOut	DB25RIB	DIGIO32	DB37RIB
Pin	Descr	Pin_26	Descr	Pin_40		Pin	Descr	Pin_26	Descr	Pin_40
1	S7	1	C1PA7	18		14	V7	2	C0PB7	20
2	G7	3	C0PA7	35		15	S6	4	C1PA6	16
3	V6	5	C0PB6	22		16	G6	6	C0PA6	33
4	S5	7	C1PA5	14		17	V5	8	C0PB5	24
5	G5	9	C0PA5	31		18	S4	10	C1PA4	12
6	V4	11	C0PB4	26		19	G4	12	C0PA4	29
7	S3	13	C1PA3	10		20	V3	14	C0PB3	28
8	G3	15	C0PA3	27		21	S2	16	C1PA2	8
9	V2	17	C0PB2	30		22	G2	18	C0PA2	25
10	S1	19	C1PA1	6		23	V1	20	C0PB1	32
11	G1	21	C0PA1	23		24	S0	22	C1PA0	4
12	V0	23	C0PB0	34		25	G0	24	C0PA0	21
13	N/C	25						26

Output Stage

Design Validation/First Article Test

• Test Code

Pass Count = 17977, Fail Count = 0

• Runs ODAS Card Test Software on Arduino Nano
• Loopback cables
  • Cable connects to DB-25 and NANO-BKOUT pins
• USB running puTTY
  • 9600 baud
• Menu driven
• Auto-detect card if test has been run before

Checking EEPROM for board type...Detected OptoIn8-I2C board
R=Read EEPROM, W=Write EEPROM, T=Test DIGIOs, L=Loop Test, B=Bounce LEDs

• Presents card type list for un-programmed EEPROMs

Checking EEPROM for board type...Company Mismatch
Select the board type
1 - DIGIO16-I2C board
2 - DIGIO-128 board
3 - OptoIn8-I2C board
4 - OptoOut8-I2C board
5 - DIGIO32-I2C board
6 - PROTO16-I2C board
7 - ODAS-PSOC5 board
8 - TBD board
9 - TBD board
Select board > 

• Select board

Select board > 3
Writing EEPROM
Initializing eep buffer
len of buffer=96
reading block
Family=ODAS
Company=land.boards.com

• Test 'T'
• Fail (no cable)

OptoIn8-I2C failed HIGH on bit 1
Read back on  1
OptoIn8-I2C failed HIGH on bit 2
Read back on  2
OptoIn8-I2C failed HIGH on bit 4
Read back on  4
OptoIn8-I2C failed HIGH on bit 8
Read back on  8
OptoIn8-I2C failed HIGH on bit 16
Read back on  16
OptoIn8-I2C failed HIGH on bit 32
Read back on  32
OptoIn8-I2C failed HIGH on bit 64
Read back on  64
OptoIn8-I2C failed HIGH on bit 128
Read back on  128
Loopback Test PASS = 0, FAIL = 1

• Pass Checking EEPROM for board type...Detected OptoIn8-I2C board

R=Read EEPROM, W=Write EEPROM, T=Test DIGIOs, L=Loop Test, B=Bounce LEDs
Loopback Test PASS = 1, FAIL = 0

Production Tests

Test Station Set-up

• Uses ODAS Test Station V2
  • DB37RIBBON - Connects to DB-37 on DIGIO32-I2C Test Station
  • DB25RIBBON - Connects to DB-25 on UUT
  • Ribbon cable set to connect 26 to 40 pin Dupont headers
• Test Station controls/read the Opto outputs via the DIGIO32 card in the Test Station
• Puts out 8 bits on OptoOut8-I2C card
• Reads the 8 bits on DIGIO32 card
• There are three lines per Channel that need to be connected:
  • Ground (Gx), Power (Vx), Open Collector Output (Sx)
  • If the LED is not being driven, the Open Collector output will be pulled up
  • Wire Grounds to Digio32 channels 0-7
  • Wire Powers to Digio32 channels 8-15
  • Wire Signals to Digio32 channels 16-23
• Resistors can be checked by setting the Power line high and checking the OC outputs
• OptoOut8-I2C card is stimulated by writing to its I2C interface
• Verifies that the Optos work

Test Steps

• Attach Host Computer USB to the Arduino NANO on the Test Station
• Run puTTY on the Host Computer
  • 9600 baud
• Enter E to access EEPROM menu
• Enter W to select the card

Select the board type
1 - DIGIO16-I2C board
2 - DIGIO-128 board
3 - OptoIn8-I2C board
4 - OptoOut8-I2C board  <<< Select 4
5 - DIGIO32-I2C board
6 - PROTO16-I2C board
7 - ODAS-PSOC5 board
8 - ODAS-RELAY16 board
A - DIGIO-128/64 board
9 - TBD board
X - Boards without EEPROMs
Select board > 

• Enter 4
• Should see

Writing EEPROM
Initializing eep buffer
len of buffer=96
reading block
Family=ODAS
Company=land-boards.com
Product=OptoOut8-I2C

• Select Card Tests = "C"
• Select Run Tests = "T"
• Observe test results

Card Debugging

• Need to set power and ground to power the OptoCoupler outputs
• Outputs via writing out the MCP23008 on the UUT
• Read back on the DIGIO32-I2C card

Setup Power and Ground

• Drive Grounds to Digio32 channels 0-7 (dec)
  • I from top menu accesses the DIGIO32-I2C
    • L command sets pins to low
      • L 0x00 through L 0x07 sets the Ground pins to Low

C=Card Tests, D=Direct, E=EEPROM, I=access Internal DIGIO32
Direct Access Test Station DIGIO32 Hardware
H=Write High, L=Write Low, R=Read a bit, X=eXit
Bit to clear Low  (HEX): 0x00
Bit to clear Low  (HEX): 0x01
Bit to clear Low  (HEX): 0x02
Bit to clear Low  (HEX): 0x03
Bit to clear Low  (HEX): 0x04
Bit to clear Low  (HEX): 0x05
Bit to clear Low  (HEX): 0x06
Bit to clear Low  (HEX): 0x07

• Drive Powers to Digio32 channels 8-15 (dec)
  • I from top menu accesses the DIGIO32-I2C
    • H command sets pins to low
      • H 0x08 through H 0x0F sets the Ground pins to Low

Bit to set High (HEX): 0x08
Bit to set High (HEX): 0x09
Bit to set High (HEX): 0x0a
Bit to set High (HEX): 0x0b
Bit to set High (HEX): 0x0c
Bit to set High (HEX): 0x0d
Bit to set High (HEX): 0x0e
Bit to set High (HEX): 0x0f

Write through UUT, Read via Internal DIGIO32-I2C

• Wire Signals to Digio32 channels 16-23
  • D command accesses the UUT
    • H or L 0x00 through H or L ox07 sets the pins high or low
• Measure signal at pullup resistor on output
  • Signal should toggle
  • X to exit menu

Bit to clear Low  (HEX): 0x00
Bit to set High (HEX): 0x00

• I from top menu accesses the DIGIO32-I2C
  • R 0x10 through 0x17 reads the output back

Drivers

• Arduino Example Code
• LandBoards MCP23008 Arduino Library
• MicroPython Library
• Raspberry Adafruit Python library - See Adafruit for latest version
• Cypress PSoC5
• Raspberry Pi Clone - Cypress PSOC5
  • DIGIO8Driver.c
  • DIGIO8Driver.h
  • ExtEEPROM.c
  • ExtEEPROM.h

Revision History

Revision X4

• Move DB-25 mounting hole to center of pins

Revision X3

• Move DB-25 left

Revision X2

• Added I2C terminators and jumpers
• Added Write enable jumper

Layout Rev x2

Revision X1

• J5 pin 1 indicator needs to be moved

Assembly Sheet

OPTO8-OUT-I2C REV X2 Assembly Sheet