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GY-63_MS5611/libraries/PCA9635/README.md
rob tillaart f357d9b81c 0.4.4 PCA9635
2023-03-17 10:31:25 +01:00

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PCA9635

Arduino library for PCA9635 I2C 8 bit PWM LED driver, 16 channel.

Description

This library is to control the I2C PCA9635 PWM extender. The 16 channels are independently configurable in steps of 1/256. This allows for better than 1% fine tuning of the duty-cycle of the PWM signal.

library is related to the 8 channel https://github.com/RobTillaart/PCA9634 class. (these might merge in the future)

Interface

#include "PCA9635.h"

Constructor

  • PCA9635(uint8_t deviceAddress, TwoWire *wire = &Wire) Constructor with I2C device address, and optional the Wire interface as parameter.
  • bool begin(uint8_t mode1_mask = PCA9634_MODE1_ALLCALL, uint8_t mode2_mask = PCA9634_MODE2_NONE) initializes the library after startup. Optionally setting the MODE1 and MODE2 configuration registers. See PCA9635.h and datasheet for settings possible.
  • bool begin(int sda, int scl, uint8_t mode1_mask = PCA9635_MODE1_ALLCALL, uint8_t mode2_mask = PCA9635_MODE2_NONE) idem, ESP32 ESP8266 only.
  • void configure(uint8_t mode1_mask, uint8_t mode2_mask) To configure the library after startup one can set the MODE1 and MODE2 configuration registers. See PCA9635.h and datasheet for settings possible.
  • bool isConnected() checks if address is available on I2C bus.
  • uint8_t channelCount() returns the number of channels = 16.

LedDriverMode

Configure LED behaviour.

  • uint8_t setLedDriverMode(uint8_t channel, uint8_t mode) mode is 0..3 See datasheet for full details.
  • uint8_t getLedDriverMode(uint8_t channel) returns the current mode of the channel.
LED mode Value Description
PCA9635_LEDOFF 0x00 led is 100% off, default @startup
PCA9635_LEDON 0x01 led is 100% on.
PCA9635_LEDPWM 0x02 set LED in PWM mode, 0..255
PCA9635_LEDGRPPWM 0x03 add LED to the GRPPWM*

* all LEDs in the group GRPPWM can be set to the same PWM value in one set. This is ideal to trigger e.g. multiple LEDs (servo's) at same time.

Read and write

Read and write individual values to LED channels. Requires LEDs' DriverMode of the specific channels to be in PWM mode.

  • uint8_t write1(uint8_t channel, uint8_t value) writes a single 8 bit PWM value.
  • uint8_t write3(uint8_t channel, uint8_t R, uint8_t G, uint8_t B) writes three consecutive PWM registers. typical use is to write R, G, B values for a full colour LED.
  • uint8_t writeN(uint8_t channel, uint8_t * array, uint8_t count) write count consecutive PWM registers. May return PCA9635_ERR_WRITE if array has too many elements (including channel as offset).

Mode registers

Used to configure the PCA963x general behaviour.

  • uint8_t writeMode(uint8_t reg, uint8_t value) configuration of one of the two configuration registers. Check datasheet for details.
  • uint8_t readMode(uint8_t reg) reads back the configured mode, useful to add or remove a single flag (bit masking).
  • uint8_t setMode1(uint8_t value) convenience wrapper.
  • uint8_t setMode2(uint8_t value) convenience wrapper.
  • uint8_t getMode1() convenience wrapper.
  • uint8_t getMode2() convenience wrapper.

Constants for mode registers

(added 0.3.4)

Name Value Description
PCA9635_MODE1_AUTOINCR2 0x80 Read Only, 0 = disable 1 = enable
PCA9635_MODE1_AUTOINCR1 0x40 Read Only, bit1
PCA9635_MODE1_AUTOINCR0 0x20 Read Only, bit0
PCA9635_MODE1_SLEEP 0x10 0 = normal 1 = sleep
PCA9635_MODE1_SUB1 0x08 0 = disable 1 = enable
PCA9635_MODE1_SUB2 0x04 0 = disable 1 = enable
PCA9635_MODE1_SUB3 0x02 0 = disable 1 = enable
PCA9635_MODE1_ALLCALL 0x01 0 = disable 1 = enable
----
PCA9635_MODE2_BLINK 0x20 0 = dim 1 = blink
PCA9635_MODE2_INVERT 0x10 0 = normal 1 = inverted
PCA9635_MODE2_STOP 0x08 0 = on STOP 1 = on ACK
PCA9635_MODE2_TOTEMPOLE 0x04 0 = open drain 1 = totem-pole

These constants makes it easier to set modes without using a non descriptive bit mask. The constants can be merged by OR-ing them together, see snippet:

ledArray.writeMode(PCA9635_MODE2, 0b00110100);

// would become

uint8_t mode2_mask = PCA9635_MODE2_BLINK | PCA9635_MODE2_INVERT | PCA9635_MODE2_TOTEMPOLE;
ledArray.writeMode(PCA9635_MODE2, mode2_mask);

// or even

ledArray.setMode2(PCA9635_MODE2_BLINK | PCA9635_MODE2_INVERT | PCA9635_MODE2_TOTEMPOLE);

Group PWM and frequency

Check datasheet for the details.

  • void setGroupPWM(uint8_t value) sets all channels that are part of the PWM group to value.
  • uint8_t getGroupPWM() get the current PWM setting of the group.
  • void setGroupFREQ(uint8_t value) is used for blinking the group of configured LED. Value goes from 0 to 255 with each step representing an increase of approx. 41 ms. So 0x00 results in 41 ms blinking period (on AND off) and 0xFF in approx. 10.5 s.
  • uint8_t getGroupFREQ() returns the set frequency of the PWM group.

Miscellaneous

  • int lastError() returns PCA9635_OK if all is OK, and other error codes otherwise.
Error code Value Description
PCA9635_OK 0x00 Everything went well
PCA9635_ERROR 0xFF Generic error
PCA9635_ERR_WRITE 0xFE Tries to write more elements than PWM channels
PCA9635_ERR_CHAN 0xFD Channel out of range
PCA9635_ERR_MODE 0xFC Invalid mode
PCA9635_ERR_REG 0xFB Invalid register
PCA9635_ERR_I2C 0xFA I2C communication error

SUB CALL and ALL CALL

Please read the datasheet to understand the working of SUB CALL and ALL CALL.

Since version 0.4.0 there is (experimental) support for the SUB CALL and ALL CALL functions. It needs more testing and if there are issues, please report.

AllCall is automatically activated for each device on startup.

Description

SUB CALL allows one to make groups of PCA9634 devices and control them on group level. The number of groups one can make depends on free I2C addresses on one I2C bus. Using multiple I2C buses or multiplexers will even increase the possible number. Every PCA9634 device can be member of up to three of these groups. To become member one needs to set the setSubCallAddress(nr, address) and enable it with enableSubCall(nr).

In the same way one can become member of an ALL CALL group. Typically there is only one such group but one can configure more of them by applying different addresses.

Interface

The functions to enable all/sub-addresses are straightforward:

  • bool enableSubCall(uint8_t nr) nr = 1,2,3

  • bool disableSubCall(uint8_t nr) nr = 1,2,3

  • bool isEnabledSubCall(uint8_t nr) nr = 1,2,3

  • bool setSubCallAddress(uint8_t nr, uint8_t address)

  • uint8_t getSubCallAddress(uint8_t nr)

  • bool enableAllCall()

  • bool disableAllCall()

  • bool isEnabledAllCall()

  • bool setAllCallAddress(uint8_t address)

  • uint8_t getAllCallAddress()

OutputEnable

Since 0.4.3 (experimental) support to control the OE (Output Enable) pin of the PCA9635. This OE pin can control all LEDs simultaneously. It also allows to control multiple PCA9634 modules by connecting the OE pins. Think of simultaneous switching ON/OFF or get dimming with a high frequency PWM. Or use 2 modules alternatively by placing an inverter in between.

See datasheet for the details

  • bool setOutputEnablePin(uint8_t pin = 255) sets the IO pin to connect to the OE pin of the PCA9635. A value of 255 indicates no pin set/selected. Sets the OE pin to HIGH. Returns true on success.
  • bool setOutputEnable(uint8_t value) Sets the OE pin HIGH or LOW. All non zero values are LOW. Returns true on success.
  • uint8_t getOutputEnable() get the current value of the OE pin. If pin is not set/selected it will return HIGH.

Note: the OE is LOW active. The user has to set the power on value by means of a PULL UP / DOWN resistor.

I2C Software reset

The goal of this function is to reset ALL PCA9635 devices on the bus. When using the software reset, ALL devices attached to the bus are set to their hardware startup conditions. Generally, there are multiple definitions of software resets by the I2C inventor NXP. To accommodate this, two different modes for this function have been defined and tested (see PCA9634).

  • Method 1 is a tested method which is specific to the PCA9634. Since the number of different types of I2C chips is very large, side-effects on other chips might be possible. Before using this method, consult the data sheets of all chips on the bus to mitigate potential undefined states.
  • Method 0 is a somewhat “general” method which resets many chips on the I2C-bus. However, this method DOES NOT reset the PCA9635 chip. Therefore, consult the data sheet of all different chips on the bus to mitigate potential undefined states.

When only working with PCA9635 chips on a bus, only method 1 is required.

ledArray.I2C_SoftwareReset(1);  //  for method 1
ledArray.I2C_SoftwareReset(0);  //  for method 0

In case you experience issues with this function on your chips (non-PCA9635), please give feedback, so the documentation can be improved.

For further details of the development, see - #10 (PCA9634 repo)

Future

Must

  • improve documentation

Should

  • move code from .h to .cpp
  • unit tests
    • SUB CALL if possible?
    • ALL CALL if possible?
  • add examples
  • improve error handling (0.5.0)
    • return values etc.
    • documentation.

Could

  • sync with PCA9634 developments
  • merge with PCA9634 and a PCA963X base class if possible
  • restructure function groups
    • in .cpp to match .h
    • readme.md

Wont