DIGIO32-I2C

Features

• 32-bit Digital I/O
  • Two MCP23017 16-bit I2C I/O Expanders
• 24LC024 ODAS Personality EEPROM
  • pid = 6
  • Write Enable jumper protects EEPROM against accidental damage
• I/O Connector is inexpensive/standard DB-37 Female
• I2C Interface
  • Daisy-chain I2C connector
  • I2C Termination jumpers for end of I2C chain
  • I2C Address select jumper (2 addresses - can support up to 4 cards)
• Power Options
  • Supports 3.3V or 5V signal levels
  • Fuse protected power output on DB-37
• Power connector (not required for minimal loads
• ODAS form factor (width is 95 mm)
• 6-32 Mounting holes

Connectors

J1 - Power

• Optional use since card can be powered from I2C Daisy-chain connector pins
• Pinout

1. GND
2. Vcc
3. GND
4. Vcc
5. GND

J2 - Daisy-Chained I2C

• 2x4 header
• Duplicated signals on each pair

1. SCL
2. SDA
3. Vcc
4. GND

J3 - Address Offset Jumpers

• Set the address offset for the MCP23017 and EEPROM
• MCP23017 base addresses are 0x20-0x21
• Card can be set to
  • 0x20-0x21
  • 0x22-0x23
  • 0x24-0x25
  • 0x26-0x27
• Jumpers orientation

J4 - Interrupt Out, Card Present

• Pinout

1. GND
2. INT1*
3. INT0*

• Card Present*

J5 - EEPROM Write Enable

• Install to allow writes to EEPROM
• Remove to disallow writes to EEPROM

J6 - I2C Terminators

• Install to terminate I2C lines
• Terminators should only be installed at one point in the chain at the end of the chain
• Orientation of jumpers

P1 - DB-37 Female Pinout

P1 - DB-37 Female Pin List

• Useful list for mapping pins to applications
• Can copy-paste this table to spreadsheet

DB37Pin	Descr		DB37Pin	Descr
1	GND		20	GND
2	C1PB7		21	C1PA0
3	C1PB6		22	C1PA1
4	C1PB5		23	C1PA2
5	C1PB4		24	C1PA3
6	C1PB3		25	C1PA4
7	C1PB2		26	C1PA5
8	C1PB1		27	C1PA6
9	C1PB0		28	C1PA7
10	N/C		29	C0PB7
11	C0PA0		30	C0PB6
12	C0PA1		31	C0PB5
13	C0PA2		32	C0PB4
14	C0PA3		33	C0PB3
15	C0PA4		34	C0PB2
16	C0PA5		35	C0PB1
17	C0PA6		36	C0PB0
18	C0PA7		37	F+5V
19	F+5V

P1 - DB-37 to DB37RIBBON Pin list

• The card canbe used with a DB37RIBBON RB-38 to ribbon adapter card
• This is the map of the pinout when used with the DB37RIBBON card
  • The DB37RIBBON adapter has a male connector when used with this card

DB37 Pin	Descr	Conn_40		DB37 Pin	Descr	Conn_40
1	GND	1		20	GND	2
2	C1PB7	3		21	C1PA0	4
3	C1PB6	5		22	C1PA1	6
4	C1PB5	7		23	C1PA2	8
5	C1PB4	9		24	C1PA3	10
6	C1PB3	11		25	C1PA4	12
7	C1PB2	13		26	C1PA5	14
8	C1PB1	15		27	C1PA6	16
9	C1PB0	17		28	C1PA7	18
10	N/C	19		29	C0PB7	20
11	C0PA0	21		30	C0PB6	22
12	C0PA1	23		31	C0PB5	24
13	C0PA2	25		32	C0PB4	26
14	C0PA3	27		33	C0PB3	28
15	C0PA4	29		34	C0PB2	30
16	C0PA5	31		35	C0PB1	32
17	C0PA6	33		36	C0PB0	34
18	C0PA7	35		37	F+5V	36
19	F+5V	37		N/C	N/C	38
N/C	N/C	39		N/C	N/C	40

Schematic

• DIGIO32-I2C Schematic

Testing

• There are two card tests
  • Bounce LED test
    • Good for visual verification/debugging
    • Only tests outputs from UUT
  • Card to card test
    • More flexible/faster test
    • Tests both inputs/outputs from/to the card

Cards

• PiPicoMite02 Based Test Station
  • PiPicoMite02 Processor card
  • LED-32
• DB37RIBBON plugged into UUT
• (2) of 2x10 cables to connect between DB37RIBBON and LED-32
  • DB37-1 marked on cable end goes near P1 marked on DB37RIBBON
• LED32-1 marked on cable end goes near HDR1 marked on LED-32
• I2C cable from Arduino Based Test Station to I2C connector on UUT
• Unit Under Test (UUT)
• Check chip pin 1 orientation
• Power test card for shorts

Card Test Procedure

• Power up Test Station/UUT

Program EEPROM

• Some UUTs have Personality EEPROMs
• Run

chdir "/lbcards/ODAS_EEPROM"
load "ODASEEPROM.bas"
run

• If the UUT EEPROM is already programmed, the result is:

Found device at 0x50
Personality EEPROM contents
 Signature = ODAS
 Version = 1
 Rsvd = 0
 NumAtoms = 2
 eeplen = 96
 uuid = 0000000000000000
 Product ID = 6 (DIGIO32-I2C)
 vslen = 32
 pslen = 32
 Vendor String = LAND-BOARDS.COM
 Product String = DIGIO32-I2C
Re-write (Y/N)?

Bounce LED Test

• Shown with BLACK-PILL-HUB based card test station

• Cable DB-37 to LED-32 card
• Runs DIGIO32I2C-01.bas code
• Type

chdir "/lbcards/GPIO32"
load "DIGIO32I2C-01.bas"
run

• Should see the LEDs go around the LED-32 card
• Hit any key to stop (after finishing rotation)

Card-to-Card Test

• Alternate to Bounce LED test
• Runs DIGIO32I2C-02.bas code
• (2) DB37RIBBON cards
• Cables to connect two DB37RIBBON cards
• Type

load "DIGIO32I2C-02.bas"
run

• Program will halt if failure
• Prints out a pass count
• Hit any key to stop

Drivers

• GitHub repo for the DigIO32-I2C Card Arduino Driver
  • Importing an Arduino ZIP library
• GitHub repo for the DigIO32-I2C Card Arduino examples

Assembly Sheet

• DIGIO32-I2C Assembly Sheet