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Driver i2c-mlxcpld
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Author: Michael Shych <[email protected]>
This is the Mellanox I2C controller logic, implemented in Lattice CPLD
device.
Device supports:
- Master mode.
- One physical bus.
- Polling mode.
This controller is equipped within the next Mellanox systems:
"msx6710", "msx6720", "msb7700", "msn2700", "msx1410", "msn2410", "msb7800",
"msn2740", "msn2100".
The next transaction types are supported:
- Receive Byte/Block.
- Send Byte/Block.
- Read Byte/Block.
- Write Byte/Block.
Registers:
=============== === =======================================================================
CPBLTY 0x0 - capability reg.
Bits [6:5] - transaction length. b01 - 72B is supported,
36B in other case.
Bit 7 - SMBus block read support.
CTRL 0x1 - control reg.
Resets all the registers.
HALF_CYC 0x4 - cycle reg.
Configure the width of I2C SCL half clock cycle (in 4 LPC_CLK
units).
I2C_HOLD 0x5 - hold reg.
OE (output enable) is delayed by value set to this register
(in LPC_CLK units)
CMD 0x6 - command reg.
Bit 0, 0 = write, 1 = read.
Bits [7:1] - the 7bit Address of the I2C device.
It should be written last as it triggers an I2C transaction.
NUM_DATA 0x7 - data size reg.
Number of data bytes to write in read transaction
NUM_ADDR 0x8 - address reg.
Number of address bytes to write in read transaction.
STATUS 0x9 - status reg.
Bit 0 - transaction is completed.
Bit 4 - ACK/NACK.
DATAx 0xa - 0x54 - 68 bytes data buffer regs.
For write transaction address is specified in four first bytes
(DATA1 - DATA4), data starting from DATA4.
For read transactions address is sent in a separate transaction and
specified in the four first bytes (DATA0 - DATA3). Data is read
starting from DATA0.
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