IC_DATA_CMD
Name: I2C Rx/Tx Data Buffer and Command Register;
this is the register the CPU writes to when
filling the TX FIFO and the CPU reads from when
retrieving bytes from RX FIFO
Size:
Write
11 bits when IC_EMPTYFIFO_HOLD_MASTER_EN=1
9 bits when IC_EMPTYFIFO_HOLD_MASTER_EN=0
Read
12 bits when IC_FIRST_DATA_BYTE_STATUS = 1
8 bits when IC_FIRST_DATA_BYTE_STATUS = 0
Address Offset: 0x10
Read/Write Access: Read/Write
NOTE: With nine bits required for writes,
the DW_apb_i2c requires 16-bit data on the
APB bus transfers when writing into the
transmit FIFO. Eight-bit transfers remain for
reads from the receive FIFO.
Module Instance | Base Address | Register Address |
---|---|---|
i_i2c_0_DW_apb_i2c_addr_block1 | 0xFFC02800 | 0xFFC02810 |
i_i2c_1_DW_apb_i2c_addr_block1 | 0xFFC02900 | 0xFFC02910 |
Size: 32
Offset: 0x10
Access: RW
Bit Fields | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 |
RSVD_IC_DATA_CMD RO 0x0 |
|||||||||||||||
15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
RSVD_IC_DATA_CMD RO 0x0 |
FIRST_DATA_BYTE RO 0x0 |
RESTART WO 0x0 |
STOP WO 0x0 |
CMD WO 0x0 |
DAT RW 0x0 |
IC_DATA_CMD Fields
Bit | Name | Description | Access | Reset | ||||||
---|---|---|---|---|---|---|---|---|---|---|
31:12 | RSVD_IC_DATA_CMD |
Reserved bits - Read Only |
RO | 0x0 | ||||||
11 | FIRST_DATA_BYTE |
Indicates the first data byte received after the address phase for receive transfer in Master receiver or Slave receiver mode. Reset value : 0x0 Dependencies: This Register bit value is applicable only when FIRST_DATA_BYTE_STATUS=1 NOTE: In case of APB_DATA_WIDTH=8, a. The user has to perform two APB Reads to IC_DATA_CMD in order to get status on 11 bit. b. Inorder to read the 11 bit, the user has to perform the first data byte read [7:0] (offset 0x10) and then perform the second read[15:8](offset 0x11) in order to know the status of 11 bit (whether the data received in previous read is a first data byte or not). c. The 11th bit is an optional read field, user can ignore 2nd byte read [15:8] (offset 0x11) if not interested in FIRST_DATA_BYTE status.
|
RO | 0x0 | ||||||
10 | RESTART |
This bit controls whether a RESTART is issued before the byte is sent or received. This bit is available only if IC_EMPTYFIFO_HOLD_MASTER_EN is configured to 1. 1 - If IC_RESTART_EN is 1, a RESTART is issued before the data is sent/received (according to the value of CMD), regardless of whether or not the transfer direction is changing from the previous command; if IC_RESTART_EN is 0, a STOP followed by a START is issued instead. 0 - If IC_RESTART_EN is 1, a RESTART is issued only if the transfer direction is changing from the previous command; if IC_RESTART_EN is 0, a STOP followed by a START is issued instead. Reset value: 0x0
|
WO | 0x0 | ||||||
9 | STOP |
This bit controls whether a STOP is issued after the byte is sent or received. This bit is available only if IC_EMPTYFIFO_HOLD_MASTER_EN is configured to 1. 1 - STOP is issued after this byte, regardless of whether or not the Tx FIFO is empty. If the Tx FIFO is not empty, the master immediately tries to start a new transfer by issuing a START and arbitrating for the bus. 0 - STOP is not issued after this byte, regardless of whether or not the Tx FIFO is empty. If the Tx FIFO is not empty, the master continues the current transfer by sending/receiving data bytes according to the value of the CMD bit. If the Tx FIFO is empty, the master holds the SCL line low and stalls the bus until a new command is available in the Tx FIFO. Reset value: 0x0
|
WO | 0x0 | ||||||
8 | CMD |
This bit controls whether a read or a write is performed. This bit does not control the direction when the DW_apb_i2c acts as a slave. It controls only the direction when it acts as a master. 1 = Read 0 = Write When a command is entered in the TX FIFO, this bit distinguishes the write and read commands. In slave-receiver mode, this bit is a 'don't care' because writes to this register are not required. In slave-transmitter mode, a '0' indicates that CPU data is to be transmitted and as DAT or IC_DATA_CMD[7:0]. When programming this bit, you should remember the following: attempting to perform a read operation after a General Call command has been sent results in a TX_ABRT interrupt (bit 6 of the IC_RAW_INTR_STAT register), unless bit 11 (SPECIAL) in the IC_TAR register has been cleared. If a '1' is written to this bit after receiving a RD_REQ interrupt, then a TX_ABRT interrupt occurs. NOTE: It is possible that while attempting a master I2C read transfer on DW_apb_i2c, a RD_REQ interrupt may have occurred simultaneously due to a remote I2C master addressing DW_apb_i2c. In this type of scenario, DW_apb_i2c ignores the IC_DATA_CMD write, generates a TX_ABRT interrupt, and waits to service the RD_REQ interrupt. Dependencies: This field is not applicable when IC_ULTRA_FAST_MODE=1 Reset value: 0x0
|
WO | 0x0 | ||||||
7:0 | DAT |
This register contains the data to be transmitted or received on the I2C bus. If you are writing to this register and want to perform a read, bits 7:0 (DAT) are ignored by the DW_apb_i2c. However, when you read this register, these bits return the value of data received on the DW_apb_i2c interface. Reset value: 0x0 |
RW | 0x0 |