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ergodox-firmware/src/keyboard/ergodox/mcp23018.md

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*lots* of stuff .. :) - got PWM working! also, i didn't make a note of it in the *.md file, but Waveform Generation Mode 15 for fast PWM wasn't working right (well.. wasn't working how i expected it to). i misinterpreted what the modes were doing, partially (haha, or all-ly?) because i didn't read the description of fast pwm thoroughly enough... in any case, all the information's in the datasheet, and it's actually not terribly long. i'm not sure how to correctly use Mode 15 yet, but i think i'll leave it alone for now, since Mode 5 works as expected, and i think what the datasheet says about *that* makes enough sense to me for me to be content for the moment.
2012-03-19 08:01:41 +01:00
# Documentation : MCP23018
## Pinouts and Pin assignments
* `+` indicates pin
* `o` indicates unused pin
* `-`s inserted between some of the pin functions for readability
* `OC**` pins enclosed in parenthesis had lines over them in the pinout
### MCP23018
Vss(GND) +01---.---28+ NC
NC +02 27+ GPA7
GPB0 +03 26+ GPA6
GPB1 +04 25+ GPA5
GPB2 +05 24+ GPA4
GPB3 +06 23+ GPA3
GPB4 +07 22+ GPA2
GPB5 +08 21+ GPA1
GPB6 +09 20+ GPA0
GPB7 +10 19+ INTA
Vdd(Vcc) +11 18+ INTB
SCL +12 17+ NC
SDA +13 16+ RESET
NC +14-------15+ ADDR
### MCP32018 Pin Assignments
power_negative Vss(GND) +01---.---28o
o02 27o
column0 GPB0 +03 26o
column1 GPB1 +04 25+ GPA5 rowB
column2 GPB2 +05 24+ GPA4 rowA
column3 GPB3 +06 23+ GPA3 row9
column4 GPB4 +07 22+ GPA2 row8
column5 GPB5 +08 21+ GPA1 row7
column6 GPB6 +09 20+ GPA0 row6
o10 19o
power_positive Vdd(Vcc) +11 18o
I2C SCL +12 17o
few things; mostly, I2C works now!; it was a hardware error i had been leaving the RESET pin floating... this does not work. it must be externally biased - high, if you want the chip to work.. :) lol
2012-04-01 02:02:55 +02:00
I2C SDA +13 16+ RESET (see note)
*lots* of stuff .. :) - got PWM working! also, i didn't make a note of it in the *.md file, but Waveform Generation Mode 15 for fast PWM wasn't working right (well.. wasn't working how i expected it to). i misinterpreted what the modes were doing, partially (haha, or all-ly?) because i didn't read the description of fast pwm thoroughly enough... in any case, all the information's in the datasheet, and it's actually not terribly long. i'm not sure how to correctly use Mode 15 yet, but i think i'll leave it alone for now, since Mode 5 works as expected, and i think what the datasheet says about *that* makes enough sense to me for me to be content for the moment.
2012-03-19 08:01:41 +01:00
o14-------15+ ADDR (see note)
* notes:
* ADDR (pin15): Set slave address to `0b0100000` by connecting to Vss(GND).
(The user-defined bits are the three least significant).
few things; mostly, I2C works now!; it was a hardware error i had been leaving the RESET pin floating... this does not work. it must be externally biased - high, if you want the chip to work.. :) lol
2012-04-01 02:02:55 +02:00
* RESET (pin16) must be externally biased. At least, this is true on the
MCP23017, so it seems like it should be true with the MCP23018. Since
we're not going to trigger it ourselves, we'll tie it high.
* <http://davidn.org/wp/?p=89>
* <http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1293498979>
*lots* of stuff .. :) - got PWM working! also, i didn't make a note of it in the *.md file, but Waveform Generation Mode 15 for fast PWM wasn't working right (well.. wasn't working how i expected it to). i misinterpreted what the modes were doing, partially (haha, or all-ly?) because i didn't read the description of fast pwm thoroughly enough... in any case, all the information's in the datasheet, and it's actually not terribly long. i'm not sure how to correctly use Mode 15 yet, but i think i'll leave it alone for now, since Mode 5 works as expected, and i think what the datasheet says about *that* makes enough sense to me for me to be content for the moment.
2012-03-19 08:01:41 +01:00
## Notes about Registers
register address function (for all bits)
-------- ------- -----------------------
IODIRA 0x00 \ 1: set corresponding pin as input
IODIRB 0x01 / 0: set ................. as output
GPPUA 0x0C \ 1: set corresponding pin internal pull-up on
GPPUB 0x0D / 0: set .......................... pull-up off
GPIOA 0x12 \ read: returns the value on the port
GPIOB 0x13 / write: modifies the OLAT register
OLATA 0x14 \ read: returns the value of this register
OLATB 0x15 / write: modifies the output latches that control the
pins configured as output
* IOCON (see datasheet section 1.6, table 1-5, register 1-8)
* BANK: bit 7; read/write; default = 0
* 1: The registers associated with each port are separated into different
banks
* 0: The registers are in the same bank (addresses are sequential)
* SEQOP: bit 5; read/write; default = 0
* 1: Sequential operation disabled, address pointer does not increment
* 0: Sequential operation enabled, address pointer increments
* notes:
* All addresses given for IOCON.BANK = 0, since that's the default value of
the bit, and that's what we'll be using.
intermitent checkin; lots of stuff; i2c on hold; kb logic in progress
2012-03-27 12:06:52 +02:00
* Outputs are open drain, so we want pull-up resistors set for everything.
*lots* of stuff .. :) - got PWM working! also, i didn't make a note of it in the *.md file, but Waveform Generation Mode 15 for fast PWM wasn't working right (well.. wasn't working how i expected it to). i misinterpreted what the modes were doing, partially (haha, or all-ly?) because i didn't read the description of fast pwm thoroughly enough... in any case, all the information's in the datasheet, and it's actually not terribly long. i'm not sure how to correctly use Mode 15 yet, but i think i'll leave it alone for now, since Mode 5 works as expected, and i think what the datasheet says about *that* makes enough sense to me for me to be content for the moment.
2012-03-19 08:01:41 +01:00
* abbreviations:
* IODIR = I/O Direction Register
* IOCON = I/O Control Register
* GPPU = GPIO Pull-Up Resistor Register
* GPIO = General Purpose I/O Port Register
* OLAT = Output Latch Register
## I&sup2;C Device Protocol (see datasheet section 1.3, figure 1-1)
intermitent checkin; lots of stuff; i2c on hold; kb logic in progress
2012-03-27 12:06:52 +02:00
S : Start OP : Device opcode
SR : Restart ADDR : Device address
P : Stop Dout : Data out from MCP23018
W : Write Din : Data in to MCP23018
R : Read
*lots* of stuff .. :) - got PWM working! also, i didn't make a note of it in the *.md file, but Waveform Generation Mode 15 for fast PWM wasn't working right (well.. wasn't working how i expected it to). i misinterpreted what the modes were doing, partially (haha, or all-ly?) because i didn't read the description of fast pwm thoroughly enough... in any case, all the information's in the datasheet, and it's actually not terribly long. i'm not sure how to correctly use Mode 15 yet, but i think i'll leave it alone for now, since Mode 5 works as expected, and i think what the datasheet says about *that* makes enough sense to me for me to be content for the moment.
2012-03-19 08:01:41 +01:00
S OP W ADDR ----> Din ... Din --> P
|
|--> SR OP R Dout ... Dout ---> P
intermitent checkin; lots of stuff; i2c on hold; kb logic in progress
2012-03-27 12:06:52 +02:00
|<--------------------------|
*lots* of stuff .. :) - got PWM working! also, i didn't make a note of it in the *.md file, but Waveform Generation Mode 15 for fast PWM wasn't working right (well.. wasn't working how i expected it to). i misinterpreted what the modes were doing, partially (haha, or all-ly?) because i didn't read the description of fast pwm thoroughly enough... in any case, all the information's in the datasheet, and it's actually not terribly long. i'm not sure how to correctly use Mode 15 yet, but i think i'll leave it alone for now, since Mode 5 works as expected, and i think what the datasheet says about *that* makes enough sense to me for me to be content for the moment.
2012-03-19 08:01:41 +01:00
|
|--> SR OP W ADDR ... Din --> P
|
|--> P
S OP R ----> Dout ... Dout --> P
|
|--> SR OP R Dout ... Dout ---> P
|<--------------------------|
|
|--> SR OP W ADDR Din ... Din --> P
|
|--> P
Byte and Sequential Write
-------------------------
Byte : S OP W ADDR --> Din --> P
Sequential : S OP W ADDR --> Din ... Din --> P
Byte and Sequential Read
------------------------
Byte : S OP W ADDR --> SR OP R Dout --> P
Sequential : S OP W ADDR --> SR OP R Dout ... Dout --> P
* notes:
* We'll be using sequential mode (ICON.SEQOP = 0; default) (see datasheet
section 1.3.1).
-------------------------------------------------------------------------------
intermitent checkin; lots of stuff; i2c on hold; kb logic in progress
2012-03-27 12:06:52 +02:00
Copyright &copy; 2012 Ben Blazak <benblazak.dev@gmail.com>
Released under The MIT License (MIT) (see "license.md")
Project located at <https://github.com/benblazak/ergodox-firmware>
*lots* of stuff .. :) - got PWM working! also, i didn't make a note of it in the *.md file, but Waveform Generation Mode 15 for fast PWM wasn't working right (well.. wasn't working how i expected it to). i misinterpreted what the modes were doing, partially (haha, or all-ly?) because i didn't read the description of fast pwm thoroughly enough... in any case, all the information's in the datasheet, and it's actually not terribly long. i'm not sure how to correctly use Mode 15 yet, but i think i'll leave it alone for now, since Mode 5 works as expected, and i think what the datasheet says about *that* makes enough sense to me for me to be content for the moment.
2012-03-19 08:01:41 +01:00
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