MCP23017 testing notes

I am reading my old posts to refresh my memory on how did I test the MCP23017 last time.
MCP23017 test preparation notes

2012年12月31日 下午2:34公開累計瀏覽次數 00

 

 

Now I have extended the 5V0 level I2C and UART signals from the pent level shifter proto board to the half size bread board.  I have tested the toggled output of 5V0 IO2 (TxD pin) to be 4.97V high and 0.11 V low.

So far so good.  Next step is playing with MCP23017.

.END

MCP23017 pinout diagram

2012年12月31日 下午3:22公開累計瀏覽次數 130

 

Now I am looking at the MCP23017 pinout diagram to remind me how last time I wired the similar thing MCP23008.

.END

MP23017 detection OK

2012年12月31日 下午3:58公開累計瀏覽次數 40

 

Now I have detected MCP23017 OK.  I made two mistakes in the wiring, luckily there is no white smoke appearing.  Finally I detected the thing successfully.  I only made the following connections.

pin 09 Vdd - 5V0

pin 10 Vss - Gnd

pin 12 SCL - RPi SCL

pin 13 SDA - Rpi SDA

pin 15 A0 - Gnd

pin 16 A1 - Gnd

pin 17 A2 - Gnd

pin 18 Reset - 5V0

So far so good.  Next step is to let the Raspberry Pi to talk to the MCP23017.

.END

SN74LVC245AN specification

2012年12月31日 下午4:38公開累計瀏覽次數 70

 

SN74LVC245AN spec

.ENd

MCP23017 proto board assembly notes

2012年12月31日 下午10:57公開累計瀏覽次數 30

 

Now I have started soldering my very first MCP23017 proto board.  I am glad that now the circuit is all 5V only, no more 3V3 blocking the way, and keeping me worrying of shorting 3V3 and 5V0 by mistake and white smoke appears.

.END

MCP23012 proto board asembly notes

2013年1月1日 下午12:45公開累計瀏覽次數 70

 

So I have moved the MCP23017 circuit from breadboard to protoboard.  I used the command "sudo i2cdetect -y 1" to verify that the address jumpers A2 A1 A0 can set the I2C address from 20 to 27 as expected, and that the reset when shorted to ground would disable the MCP23017 and therefore could not be detected anymore.

.END

MCP23017 interrupt LED assembly notes

2013年1月1日 下午9:28公開累計瀏覽次數 20

 

Now I have added two red/green LED pairs to indicate the status of MCP23008's INTA and INTB.  Offline testing good.

.END

Raspberry Pi MCP23017 evaluation board and testing plan

2013年1月2日 上午11:41公開累計瀏覽次數 280

 

Now I have completed all the soldering work of the MCP23017 evaluation board.  Next step is testing.

.END

Raspberry Pi MCP23017 Port Expander Board Kit - HobbyTronics, UK

http://www.hobbytronics.co.uk/mcp23017-port-expander-board

This useful kit contains the MCP23017 Port Expander chip and a breakout board which connects directly to our Raspberry Pi GPIO Breakout Board and plugs into a Breadboard. The Power and I2C connections are automatically made to the GPIO Breakout Board via a 5 way header socket so no breadboard wiring is needed.

Features

Connects directly to GPIO Breakout Board via 5 pin header

Pull up resistor on RESET pin of MCP23017

Pull down resistors on addess pins of MCP23017 to give default address of 0x20

Multiple boards can be linked together

The 16-bit I/O port functionally of the MCP23017 consists of two 8-bit ports (PORTA and PORTB). The MCP23017 can be configured to operate in 8-bit or 16-bit modes

This is a kit and requires soldering.

The kit contains

Port Expander PCB

MCP23017 IC

IC Socket

2 x 14 way header pins

5 way right angle socket

5 way right angle header pins

Documents

MCP23017 Port Expander Board Schematic

http://www.hobbytronics.co.uk/datasheets/rpi_mcp23017_port_expander.pdf

Raspberry Pi Raspbian Distro Installation and GPIO Port

http://www.hobbytronics.co.uk/tutorials-code/raspberry-pi-tutorials/raspberry-pi-raspbian-distro

4-Way Bi-directional Logic Level Converter

http://www.hobbytronics.co.uk/logic-level-4

.END

MCP23017 testing notes

2013年1月2日 下午3:38公開累計瀏覽次數 30

 

Now I have started modifying the MCP23008 functions to do MCP23017.  There are altogether 22 internal registers, double of that of MCP23008.  I have not understood how the banks are working.  So I just blindly make the changes.  The 22 regsters has the following values.

# * MCP23017 Register addresses *

MCP23017_1_REGISTER_BASE_ADDRESS = 0x22

MCP23017_2_REGISTER_BASE_ADDRESS = 0x23

IO_DIRECTION_REGISTER_A_BANK_0 = IODIRA_B0 = 0x00

IO_DIRECTION_REGISTER_B_BANK_0 = IODIRB_B0 = 0x01

INPUT_POLARITY_REGISTER_A_BANK_0 = IPOLA_B0 = 0x02

INPUT_POLARITY_REGISTER_B_BANK_0 = IPOLB_B0 = 0x03

INTERRUPT_ON_CHANGE_REGISTER_A_BANK_0 = GPINTENA_B0 = 0x04

INTERRUPT_ON_CHANGE_REGISTER_B_BANK_0 = GPINTENB_B0 = 0x05

DEFAULT_COMPARE_VALUE_REGISTER_A_BANK_0 = DEFVALA_B0 = 0x06

DEFAULT_COMPARE_VALUE_REGISTER_B_BANK_0 = DEFVALB_B0 = 0x07

INTERRUPT_CONTROL_REGISTER_A_BANK_0 = INTCONA_B0 = 0x08

INTERRUPT_CONTROL_REGISTER_B_BANK_0 = INTCONB_B0 = 0x09

IO_CONTROL_REGISTER_A_BANK_0 = IOCONA_B0 = 0x0a

IO_CONTROL_REGISTER_B_BANK_0 = IOCONB_B0 = 0x0b

PULL_UP_RESISTOR_CONFIG_REGISTER_A_BANK_0 = GPPUA_B0 = 0x0c

PULL_UP_RESISTOR_CONFIG_REGISTER_B_BANK_0 = GPPUB_B0 = 0x0d

INTERRUPT_FLAG_REGISTER_A_BANK_0 = INTFA_B0 = 0x0e

INTERRUPT_FLAG_REGISTER_B_BANK_0 = INTFB_B0 = 0x0f

INTERRUPT_CAPTURE_REGISTER_A_BANK_0 = INTCAPA_B0 = 0x10

INTERRUPT_CAPTURE_REGISTER_B_BANK_0 = INTCAPB_B0 = 0x11

GPIO_REGISTER_A_BANK_0 = GPIOA_B0 = 0x12

GPIO_REGISTER_B_BANK_0 = GPIOB_B0 = 0x13
.END

.END