OptoOut8-I2C

Features

• Eight optically-isolated output channels on card
  • (8) 4N25 optoisolators
• MCP23008 I2C Parallel I/O
  • I2C (Two Wire interface)
  • 100/400 KHZ operation
  • 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 ODAS Personality EEPROM
  • pid = 5
  • 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
  • 25mA sink/source capability per I/O
    • Maximum current out of VSS pin = 150 mA
    • Maximum current into VDD pin = 125 mA

• LED Current vs voltage

• Output transistor capacitance

• Switching Time

• Opto Characteristics

Vcc	5.000	V	3.300	V
Vf LED	1.200	V	1.200	V
Res ser	330.000	Ohms	330.000	Ohms
If LED	11.515	mA	6.364	mA
CTR (min)	0.500	A/A	0.500	A/A
Iout	5.758	mA	3.182	mA
All pins Low	8		8
I(Vss pin)	92.121	mA	50.909	mA
I Max (Vss)	150.000		150.000
Loading	61.41%		33.94%

Output Stage

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

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 OptoOut8-I2C card using this procedure.

Test Station Theory of Operations

• 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 Station Set-up

• Uses ODAS Test Station V2
  • DB37RIBBON (w/ male connector) - Connects to DB-37 on DIGIO32-I2C Test Station
  • DB25RIBBON (w/ male connector) - Connects to DB-25 on UUT
  • Ribbon cable set to connect DB25RIBBON to DB37RIBBON pin Dupont headers
• Unit Under Test (UUT)
  • Install 6x jumpers (A0-A2, SDA/SCL I2C terminators, and WEN jumpers)
• ODASTESTER Tester GitHub Repo
• Attach Host Computer USB to the Arduino NANO on the Test Station
• Run puTTY on the Host Computer
  • 9600 baud

EEPROM Programming

• First time the UUT card is tested, the Test Station auto-detects that the card has an unprogrammed EEPROM
• Test Station also determines that the card has (1) MCP23008 and presents menu
  • If the wrong cards are listed, verify jumpers (as above) are installed on UUT

Checking if EEPROM is present on UUT...EEPROM is present on UUT
Checking EEPROM for board type...Board signature error in EEPROM on UUT
Count of I2C devices in range 0x20-0x27 on UUT = 1
No external I2C mux card
Detected MCP23008
Select the board type (EEPROM)
3 - OptoIn8-I2C board
4 - OptoOut8-I2C board
9 - TBD board
X - Boards without EEPROMs
Select board > 

• Enter 4
• Test Station will program EEPROM and print

Writing EEPROM
Initializing eep buffer
len of buffer=96
reading block
Family=ODAS
Company=land-boards.com
Product=OptoOut8-I2C
C=Card Tests, D=Direct, E=EEPROM, I=access Internal DIGIO32

• After first time card is powered up, menu will show

Checking if EEPROM is present on UUT...EEPROM is present on UUT
Checking EEPROM for board type...Detected OptoOut8-I2C board
Count of I2C devices in range 0x20-0x27 on UUT = 1
No external I2C mux card
C=Card Tests, D=Direct, E=EEPROM, I=access Internal DIGIO32

Running card Test

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

Testing UUT = OptoOut8-I2C
Test PASS = 1, FAIL = 0

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 Internal to Test Station
    • 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 Internal to Test Station
    • 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 4 (2022-9)

• Move to KiCad 6
• Move DB-25 to board edge
• Fix DB-25 mounting hole locations
• Add filled power layer pour on top
• Improve legends
• Order new batch of boards
  • Tested first board, passed all tests

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 4 Assembly Sheet
• OPTO8-OUT-I2C REV X2 Assembly Sheet