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This commit is contained in:
Neil McKechnie 2023-02-25 11:42:12 +00:00
parent 780c6ea162
commit c2983efebb
1 changed files with 1 additions and 12 deletions
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13
I2CManager.h
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@ -84,8 +84,6 @@
*/ */
/* /*
* Future enhancement possibility:
*
* I2C Multiplexer (e.g. TCA9547, TCA9548) * I2C Multiplexer (e.g. TCA9547, TCA9548)
* *
* A multiplexer offers a way of extending the address range of I2C devices. For example, GPIO extenders use address range 0x20-0x27 * A multiplexer offers a way of extending the address range of I2C devices. For example, GPIO extenders use address range 0x20-0x27
@ -98,11 +96,6 @@
* Thirdly, the multiplexer offers the ability to use mixed-speed devices more effectively, by allowing high-speed devices to be * Thirdly, the multiplexer offers the ability to use mixed-speed devices more effectively, by allowing high-speed devices to be
* put on a different bus to low-speed devices, enabling the software to switch the I2C speed on-the-fly between I2C transactions. * put on a different bus to low-speed devices, enabling the software to switch the I2C speed on-the-fly between I2C transactions.
* *
* Changes required: Increase the size of the I2CAddress field in the IODevice class from uint8_t to uint16_t.
* The most significant byte would contain a '1' bit flag, the multiplexer number (0-7) and bus number (0-7). Then, when performing
* an I2C operation, the I2CManager would check this byte and, if zero, do what it currently does. If the byte is non-zero, then
* that means the device is connected via a multiplexer so the I2C transaction should be preceded by a select command issued to the
* relevant multiplexer.
* *
* Non-interrupting I2C: * Non-interrupting I2C:
* *
@ -138,13 +131,9 @@
// may be extended to include multiple buses, and other features. // may be extended to include multiple buses, and other features.
// Uncomment to enable extended address. // Uncomment to enable extended address.
// //
// WARNING: When I2CAddress is passed to formatting commands such as DIAG, LCD etc,
// it should be cast to (int) to ensure that the address value is passed rather than
// the struct.
//#define I2C_EXTENDED_ADDRESS //#define I2C_EXTENDED_ADDRESS
///////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////
// Extended I2C Address type to facilitate extended I2C addresses including // Extended I2C Address type to facilitate extended I2C addresses including
// I2C multiplexer support. // I2C multiplexer support.
@ -184,7 +173,7 @@ enum I2CSubBus : uint8_t {
#endif #endif
SubBus_No, // Number of subbuses (highest + 1) SubBus_No, // Number of subbuses (highest + 1)
SubBus_None = 254, // Disable all sub-buses on selected mux SubBus_None = 254, // Disable all sub-buses on selected mux
SubBus_All = 255, // Enable all sub-buses SubBus_All = 255, // Enable all sub-buses (not supported by some multiplexers)
}; };
// Type to hold I2C address // Type to hold I2C address